Secret Agent "X" – The Complete Series, Volume 1

Death hurled a ghastly challenge at Secret Agent “X.” A torch of terror burned above Doom’s table where they played. And charred, unsightly corpses were the jackstraws dealt him by the grim gamester’s boney hand.

Chapter I

TENSELY, nervously, the four men in the semi-gloom of the padlocked speak-easy waited. Their faces gleamed in the flame of the single candle that flickered and guttered on the dust-laden bar. Their whispers disturbed the stillness of walls that had once echoed to drunken laughter and the clink of liquor glasses.

One of them was pacing restlessly. His quick, jerky steps crossed and recrossed the spot where, months before, the speak-easy’s owner had dropped under the flaming snouts of gangster guns — the spot where he had gasped out his life in a hideous welter of blood.

Sinister stains showed on the floor. Ghosts of a harrowing past seemed to lurk in dark, chill corners of the room — ghosts of murder, intrigue, and violent death.

The pacing man was “Monk” Magurren, ex-mobster and beer runner. The three with him were underworld colleagues, banded together tonight in response to a single motive — greed.

Magurren paced on, his shadow moving across the bloodstained floor like a portent of evil to come.

The others were trying to conceal their impatience. “Slats” Becker sat slumped in a chair, a limp cigarette hanging from his lower lip. “Doc” Wiser, sleek and immaculately dressed, examined his nails with studied carelessness. Tony Garino, hair black as night, face as cold and white as marble, was hunched in brooding silence.

They were a sinister crew — human wolves who had followed the lawless caravan of prohibition in the years when King Alcohol ruled the underworld. Each had made and lost a fortune. Now, like wolves denied their accustomed prey, they were hungrily out for whatever fare they could get.

Monk Magurren jerked a jeweled watch from his vest — a relic of former grandeur. His voice rasped with impatience as he glanced at the dial.

“Ten-ten. Why the hell don’t he show up? He’s got a noive keeping guys like us waiting. He’s screwy, I tell you!”

Slats Becker drew a bundle of century notes from his pocket. He spread them on the table in front of him, gestured and shrugged.

“He may be screwy — but these is real leaves he hands out. They look good to a bird who ain’t seen a greenback since your Uncle Sam put the skids under old man Volstead.”

Magurren stopped before the little gangster, stabbing a bony finger toward his face.

“Did you ever see a big shot like him?” he cracked. “Answer me that, mug!”

“So what?” said Becker carelessly. “So what?”

“He’s phony, I tell you. That’s what. He ain’t told us about the job he wants pulled.”

“It’s O.K. by me so long as there’s a little gun play,” said Becker. He patted his right-hand pocket fondly where a flat automatic rested. Those snaky, skillful hands of his had written a dozen grim pages in the black book of Death. They were ready to kill again.

“Gun play!” sneered Magurren. “You got that guy sized up wrong. He ain’t no big shot, I say. You never heard of him, did you? You never seen him before?”

The others shook their heads. Magurren, arrogant and talkative, was voicing their own secret thoughts. The man who had hired them, arranged for them to meet him here at ten, was a mystery to them. He had them guessing, worried.

Tony Garino spoke, spreading his soft, white hands.

“Maybe he’sa come in from Chi,” he said. “Or maybe he’sa just got outa stir.”

Monk Magurren snorted.

“I know all the good guys in jail this side of Frisco — an’ I don’t know this mug. He’s just a cheap crook tryin’ to get tough. He’s got his mitts on a little dough and he thinks he’s a big shot. Leave it to me to show him up, I’ll—”

The gangster stopped speaking as abruptly as he had begun. Neither he nor his cronies had heard a sound. There had been no creak of window or movement of door. The place had been deserted when they came in. But now a tall, arresting figure walked out of the gloom at the end of the bar and moved into their midst.

“Good evening, gentlemen!” The voice that spoke was low, mocking, ironic.

MONK MAGURREN crouched back, snarling in his throat like a startled animal. Slats Becker dropped his cigarette. Doc Wiser slid a tense hand into his right coat pocket, and Tony Garino made a serpent’s hiss between white teeth. All of them riveted their eyes on the man who had so suddenly and mysteriously appeared.

“Meester Jones,” said Garino, “we didn’t ’a’ hear you come in!”

The stranger surveyed them silently. His tall figure was clad in a simple, dark suit. His hair was sandy, his face ordinary looking. But there was something in his gaze that made the men in the room shift uneasily. His eyes had a burning, compelling light in them that seemed at odds with the mildness of his features. Force radiated from them. There was a glint of grim humor in their depths as though the stranger called Jones were laughing at the expense of the four gangsters.

It was Magurren who first recovered his swaggering poise.

“Well,” he said. “What is it you want us to do? Spill it!”

The stranger ignored this blunt question. He inclined his head toward the rear door of the speak-easy.

“Get going,” he snapped.

Magurren bristled.

“I don’t go blind on anything, boss. I used to be a big shot myself. I wanta know what’s up.”

“Yes?”

“Yeah. Don’t act like you was the king-pin.”

Magurren, sneering openly now, went on when the stranger who called himself Jones didn’t answer.

“We know you ain’t never had a mob before. We wanta see that you don’t get into trouble. Come on — give us the dope!”

The intense, burning light in Jones’s eyes silenced him suddenly. Jones motioned toward the door again, and somehow his mild features conveyed a note of inexorable command.

Grumblingly, the four men obeyed, filing toward the rear door of the speak-easy. Jones blew out the candle. In a moment he was ahead of them, guiding them. They crossed a courtyard of broken flags, turned through a door in a fence, and came into a side street. A big limousine was parked at the curb. It was long and low and black, with lines that suggested speed and power. There was something sinister about it, something that made the four men hesitate before getting in.

But Jones held the door open and motioned imperiously. Becker, Garino, and Wiser got into the back. Magurren climbed in front. Jones took the wheel himself.

AN uneasy silence followed as the big car slid smoothly into gear and rolled off. It gathered momentum with incredible swiftness, slipping through the dark streets almost soundlessly. The high-speed motor ran as quietly as a watch. The car was of some foreign make, and Monk Magurren noticed that, whoever Jones was, he could drive like a demon. With an ease that seemed unconscious, he wound his way through traffic, clipped corners, and sped across town.

“Where are we goin’, boss?” asked Magurren, his tone a little more respectful now.

Jones didn’t answer. He was staring straight ahead, a faint smile on his face, a smoldering light in his eyes. Magurren began to bluster again.

“We want action,” he said. “We ain’t had no excitement since all the punk grocers in town chiseled into the booze racket.”

“Action!” Jones echoed the word softly, and Magurren saw then that the big car was slowing down. They were on a familiar street — too familiar to suit Magurren. He glanced uneasily about as the car stopped. Ahead of them, down the block, was a big, gloomy building, a building with two green lights in front of it.

“Say, what’s the idea?” Magurren rasped.

Jones turned in his seat then, faced them. The light in his eyes had an almost uncanny brightness.

“Action!” he repeated. “You don’t want a soft job, do you? You want excitement. Well — you’re going to get it!”

“Whatta yer mean? Dat’s police headquarters down dere!”

“I know it. That’s where we’re going!”

The sentence was like a thunderbolt. Fury showed on the faces of the men in the car.

“Say, you double-crosser! You—”

Jones held up his hand. “Don’t get me wrong! You’re not going to have charges pressed against you. You’re going there to do a job.”

A breathless silence followed. Then Slats Becker croaked a question. “What kind of a job, boss?”

“Kidnap the commissioner!”

Disbelief, bewilderment and utter amazement showed on the faces of the four gangsters. As they saw that Jones was serious, the slow pallor of fear followed. They wanted action, but they hadn’t anticipated such an unheard-of, desperate act as this.

“You’re nuts!” said Magurren harshly. “You been feedin’ on hop if you think—”

The stranger called Jones cut him short. His mild face had suddenly assumed granite hardness. He crouched forward in his seat, seeming to tower over them.

“Four-flushers!” he barked. “Action you want, eh? Tough guys, eh?”

He laughed then, and the sound that came from his lips was like the taunting, insulting smack of fists lashing across their faces. Monk Magurren stiffened. His features became mottled with anger. The suave Doc Wiser trembled and the fingers of his right hand grew rigid as a hawk’s claw. Garino bared white teeth in a snarl. His eyes were black pools of fury.

“Listen, boss, you can’t talk like that. We’ll—”

Jones surveyed them again. His taunting laughter had accomplished its purpose, whipped their pride and conceit, made them ready to face death.

“O.K.,” he said shortly. For a moment he fumbled under his seat, and the gangsters started when they saw what was in his hands. Four black automatics. He thrust one toward each man.

“Take these,” snapped Jones. “Park the ones you’ve got in the car!”

He watched eagle-eyed to see that they obeyed. Then he issued swift instructions.

“Becker and Wiser stay outside. Magurren and Garino come with me!”

Wonderingly, tense with excitement, the gangsters followed their mysterious leader.

Two plain-clothes men were lolling outside headquarters. They grew alert as Jones approached with the others trailing him. Police automatics appeared in their hands. Headquarters was under heavy guard, and the four mobsters knew why. It made the job that Jones was trying to pull seem like utter madness.

“What’s your business?” said one of the detectives. “Stand back!”

JONES acted so quickly that it left the four gangsters breathless. His hand flashed into his coat, swift as the head of a striking snake. His fingers came out grasping a gun like the one he had given to them.

Before the detective could fire, there was a hiss, a jet of vapor, and without a sound the plain-clothes man collapsed.

Magurren, catching on, fired at the other man. The strange gas gun that Jones had given him worked perfectly. Unharmed, but completely out, both dicks lay on the sidewalk. And Jones passed inside.

He moved with lightning speed now. An alarm would soon be spread. He had to penetrate to the commissioner’s sanctum before this happened. The desperate thing he was doing depended for its success on strategy. The desk sergeant bellowed a question. Jones’s answer was another jet of vapor from the muzzle of his own gas gun. With a grunt the sergeant collapsed behind his desk.

Jones seemed to know the layout of headquarters. He bounded up the stairs to the second floor, leaving Becker and Magurren on guard below. He made his way along a corridor, burst open a door that was marked: “Commissioner’s Office.”

A big man with a cigar in his mouth rose abruptly from a chair behind his desk. In one and the same movement, his hand reached toward a signal panel with many buttons on it. But Jones stopped him with a wave of his gun.

“Don’t do that, commissioner!”

The commissioner’s jaw dropped, his hand hesitated. He had distinguished features, a well-formed face, a carefully trimmed black mustache. His mustache seemed to stand out now in sharp contrast to the whiteness of his skin. Fear of death showed suddenly in his eyes.

“Who are you?” he asked.

Jones, ignoring the question, uttered an abrupt command.

“Come with me, commissioner.”

For another second the commissioner hesitated. He looked desperately about. It was late. He had dismissed his stenographer. His own cot, made up at the side of the office, testified to the fact that the police of the city were facing some sort of an emergency, a crisis so real that the commissioner felt his presence at headquarters was imperative every minute. It was this that accounted for the fear in his face. But the compelling look of the man who had burst into his office seemed to move him as much as fear.

His hands dropped limply at his sides. With a shrug he walked across the office to the door.

“Downstairs,” said Jones. “There’s a car waiting up the block. Walk toward it.”

The commissioner started for the elevator, but again Jones’s voice gave an order.

“Not that way — use the stairs.”

Like a man in a trance the police commissioner did as he was told. When he reached the floor below, he shot one frightened look toward the desk, saw that the sergeant had disappeared, and his face stiffened. A door in the rear opened suddenly. A clerk started to come out, saw what was going on, and paused. Before Jones could fire, the clerk ducked out of sight.

The commissioner swore harshly when he glimpsed the prostrate bodies of the two detectives on the sidewalk. For a moment it seemed that he was going to turn and fling himself on the man called Jones. Cords in his neck stood out. He clenched one fist. But Jones’s voice spoke softly.

“Take it easy, commissioner.”

THE four gangsters, trembling violently at sight of this highest official of the city’s police, closed in. It seemed that they wanted to hide their faces. They were like men clutching a bomb. They feared to keep it — and feared to drop it.

Jones gestured toward the car up the block. The commissioner moved forward mechanically.

When he was still twenty feet from it, there was a sudden sound behind. It was the shrill, ghostly wail of a police siren. A radio cruiser was coming up to headquarters. Jones heard startled cries as the cops in the car saw the two unconscious detectives on the sidewalk.

He flung open the door of the powerful car.

“Get in,” he said harshly. The commissioner obeyed, and Jones ran around the side of the car and jerked open the door of the driver’s compartment.

As he slipped under the wheel, with Magurren crouched tensely on the other side, hell seemed to break loose behind them. A squad of uniformed cops who had been lounging in the barrack room at headquarters, poured into the street. The frightened clerk had given the alarm. One of the cops had a riot gun. He knelt, aiming for the tires of Jones’s car.

But Jones spun the wheel of the big sedan viciously, sent it shooting away from the curb in a dizzy arc. It seemed to spring over the pavement like a live thing. The police cruiser, with headlights glaring and spotlight turned on, came after them. The riot gun in the cop’s hand stuttered into life, and a stream of low-flying bullets narrowly missed the big car’s tires. One of them struck a hub cap. Metal popped and cracked, and the bullet screamed away into the darkness.

Jones, crouching over the wheel, spun around a corner. The engine under the big hood in front of him rose from a subdued purr into a muffled, throaty whine of gusty power. A hundred foam-flecked horses seemed to be whirling the car ahead through space. Then somewhere in the distance a police siren sounded — a second, third, and fourth gave answer. All the radio cruisers in the city appeared to be converging upon them, rushing to the scene of this most brazen and unparalleled of crimes.

Chapter II

THE four gangsters and the commissioner in the car with Jones were never to forget that ride. A madman seemed to be at the vehicle’s wheel. Yet a madman with such uncanny skill that the big sedan responded as though it had the ability to hear and obey human commands.

It roared past an intersection, and two green police cruisers nosed out of side streets ahead. They came from opposite directions, stopped abruptly with squealing brakes. A score of short-wave radios were picking up the frantic appeals from headquarters. But the cops were in a tight spot. They couldn’t fire on the speeding sedan without risking the life of the commissioner.

The patrolmen, therefore, sought to block the street, make the racing car slow down, and perhaps get a shot at the driver. To save the commissioner from what seemed certain death, a desperate gamble of some sort was necessary. They edged in at an angle across the street. The plunging sedan tore on.

At the last moment Monk Magurren, tough killer that he was, swore harshly, fearfully, under his breath. Slats Becker closed his eyes and gripped the tasseled cord that hung from the car’s interior. The commissioner sat frozen with a glassy stare, swaying to the movements of the rocketing car like a propped-up corpse. Certain destruction appeared to stare them in the face.

The police cruisers shrieked their sirens in warning. A cop with a gun in his hand leaned out. He waved frantically, ordering the black car to slow down. It came on like a roaring, lurching fury.

The drivers of the cruisers tried to back away. It would have been too late in any event. It was the man at the wheel of the black sedan who saved the situation.

His mild-featured face set in mask-like immobility, he swung the car deliberately toward the curb. His sharp eyes had glimpsed a driveway leading to a garage. The sidewalk was empty. The car’s fat tires cut into the driveway at a sharp angle. The car reared up, whizzed forward, and for dizzy, perilous seconds tore along the pavement itself with a wall on one side and the curb on the other. It passed the two glaring-eyed police cruisers.

Then Jones swung the wheel again. The big car leaped back to the level of the street. It left the five men inside bathed in cold sweat. It left the cops in their cruisers paralyzed into inaction. Jones, his face masklike as ever, applied brakes for an instant, whirled into a side street.

Over dark, rutted pavements the car sped forward. It seemed to crouch on each rise, gather speed, and leap ahead. It plunged down into the depressions like a speed-boat taking the swells.

The sirens of the radio cruisers behind resembled the confused baying of hounds that have lost the scent. They faded into the distance as the big car plunged on. Now and again, a new one sounded in front.

At such times, Jones at the wheel, bore away at right angles along some cross street. Once he cut through the uptown theater district, and again the men with him held their breaths and expected death. Grimly Jones held the siren of his own car down to clear the street of innocent pedestrians.

He whirled up a long avenue toward a section of cheap apartments. He bore across town again, till the river showed black and somber under the curtain of night. Then he struck a parkway and followed along it till he was on the edge of the suburbs.

For a moment he slowed the car’s speed, quieted the engine, and listened. Somewhere, far behind, the wailing, complaining note of a siren sounded. But it seemed to be going in the wrong direction, taking the wrong route.

Jones smiled, pressing the accelerator again. The big car sped ahead once more. Suddenly he wrenched the wheel, pulled the car’s nose around, tore through a sparse hedge that scratched and slapped against the wheels. Abruptly he bumped to a stop, extinguishing the lights.

Darkness lay all around them. They were in a vacant lot at the outskirts of the city. This strange parking space seemed to have figured in Jones’s desperate plans.

“Get out,” he said.

The gangsters obeyed now, cowed by the ride they had had, cowed by the crime they had taken part in, and by the strange, amazing actions of their new boss.

Jones himself kept close beside the commissioner. The police chief’s face indicated that he expected death. He appeared to think the vacant lot was a prearranged place of execution. But Jones led him on.

He crossed the lot with his little cavalcade following. The streets around it were deserted. A closed-down factory towered on one side, a vast bulk of blackness in the black night. Old, jumbled sheds and warehouses showed ahead. Jones picked his way toward one of these. He stopped, took a key from his pocket, and fumbled familiarly. In a moment he had opened a door and marshaled his men in. He jumped down a boarded passageway, opened another door, and entered a deserted shed.

A small pot-bellied stove was burning at one side of the room. There were bunks along the walls. It was a shed once used by a gang of laborers. Deserted and neglected, it made a snug hideout. Jones lit an oil lamp in a wall bracket. It cast a wan light over the dingy furniture. The windows were boarded up. No glow would show outside.

In brief sentences, giving no explanation of his motives, Jones ordered the commissioner to take off his clothes. When this had been done, he rolled them into a neat bundle and stuffed them under his arm. They contained all the police head’s private papers.

Stripped to shorts and an undershirt, the commissioner stood tense and waiting. The four gangsters watched with amazement and wonder. They now seemed to believe that Jones was mad. But his bright, alert eyes held them in a spell of fear.

“I’m going to leave you,” he said suddenly. “Hold the commissioner here until I come back.”

Abruptly, as though disobedience on their part was out of the question, he went to the door, opened it and disappeared into the night.

The gangsters and the commissioner, listening, thought for a moment that they heard a strange whistle floating through the darkness. It was musical, yet eerie, seeming to fill the whole air at once. Then gradually, like an echo dying in the night, it faded away, leaving only blackness and mystery behind.

THE man called Jones didn’t get back into the big car. He left it parked where it was in the vacant lot, concealed by darkness and the sparse, untrimmed hedge.

He walked briskly along the night-shrouded street — walked with the swift, easy stride of a man who has a definite objective. Once a police cruiser flashed by him, its radio crackling, two tense-faced patrolmen at the wheel. They barely noticed the darkly dressed man on the sidewalk with the bundle under his arm.

Once, a little later, Jones paused an instant in his stride to press a hand to his left side as a sudden twinge of pain stabbed close to his heart. But the pain passed and the man moved on. It was the pain of an old wound received in the flaming hell of a battlefield in France — a wound which doctors had predicted years before would kill him, but which his own amazing vitality had overcome.

He turned suddenly, entered the front gate of a house with a “For Rent” sign on it. The house was shuttered and boarded, but he took a passkey from his pocket, opened a side door, and let himself in. He moved across creaking floors, climbed a flight of stairs, and went to an old attic room. Here, under the sweep of low eaves, he was shut away from the whole night-darkened world. It was a temporary hideout that the strange man called Jones had possessed himself of without asking any one’s leave.

He fumbled for a moment in a closet, drew out a big suitcase. Snapping it open, he took out an assortment of strange objects. One was an acetylene lamp with an adjustable, parabolic reflector. The current in the house was turned off, but when he lit this lamp, it made the shuttered attic room as bright as day.

He took out a collapsible mirror with three sides, set it up on a shelf, and studied his reflection for a moment. Then his long fingers began to move.

The contours of his face which had characterized him as “Jones” began strangely to disappear. Under the brilliant, violet glow of the acetylene light, a new face came into being. It was a face that not even his few intimate friends had ever seen — a face, the identity of which he kept guarded with a thousand masterly disguises.

The face that stared back at him from the mirror now was not like the gang leader called Jones. The blunt, nondescript features had disappeared. The sandy hair had revealed itself as a clever toupee.

Brown hair showed above a youthful forehead. The even nose, mouth, and chin looked boyish. But, when the man turned suddenly to pick something up, the light fell on his features at a different angle. New lines appeared then, making him look suddenly older, as though, like the disguises that so cleverly concealed him, his own experiences and adventures had numbered among the thousands. It was the face of a mature, poised man of the world — the face of Secret Agent “X.”

WHO was Secret Agent “X”? Many people had asked that question. There were those who thought of him as a dangerous, desperate outlaw. The police of a dozen cities suspected him. Yet the underworld itself regarded him with hate and fear — for his life was dedicated to a strange, relentless warfare on criminals.

With unlimited resources at his command, with uncanny skill in the creation of disguises, with an utter disregard of the threat of death, he was a force that the most evil malefactors had to reckon with.

The light in his eyes was burningly intent now. He began taking other objects from his suitcase, working with a definite, sure purpose. There were tubes of plastic, volatile materials. Other tubes of shaded, flesh-tinted pigments. There were tissue-thin nose and cheek plates to change the contours of the features, strips of transparent adhesive tape to draw face muscles into new shape — all the utensils and paraphernalia of the expert craftsmen in the art of disguise.

Along with his materials in the suitcase, Agent “X” removed a half-dozen photographs of a human face. The face was stern, dignified, heavily mustached. It was the face of the commissioner of police whom he had so lately kidnapped. These Agent “X” studied for long moments. They showed the commissioner’s features from every angle.

It was a half-hour later that he rose from his seat in front of the three-sided mirror and took off his clothes. As he slipped into those he had taken from the police commissioner, even the commissioner’s best friends wouldn’t have guessed that the man in that room was other than he appeared to be.

Layer upon layer of the plastic, quick-drying material had molded “X’s” face into new lines. It was material so mobile that it followed every movement of the flesh beneath. The man standing there, buttoning up his immaculate coat was the commissioner to all intents and purposes. The wallet in his pocket, the various credentials, proved it.

In a moment more, with his hat and overcoat slipped on, he strode out into the street, ready to hurl a gambler’s challenge into the very teeth of Fate and Death.

Chapter III

FIFTEEN minutes later, a cop quietly patrolling his beat saw a staggering, reeling figure coming toward him. The cop gripped his nightstick, held himself tautly alert, then gasped. He leaped forward with a cry of amazement and concern.

The face of the staggering man, seen in the radiance of a street light, was familiar.

“Commissioner Foster!” the cop gasped.

The commissioner seemed too weak and dazed to reply. He collapsed on the sidewalk. His hat fell beside him. The cop saw a red welt on the commissioner’s forehead. It was obvious he had been struck down by the men who had kidnapped him. He seemed to be suffering from amnesia.

The cop blew his whistle. An answering blast sounded far down the block. Another cop came running. This second patrolman, when he found what the excitement was, rushed into a house and put in a call to headquarters. The call was answered by two patrol cars and by a special police ambulance.

But by the time they arrived, the commissioner seemed to have regained his faculties. He was standing on his feet, aided by the cop who had first seen him. His hat was back on his head.

He waved the ambulance interns away impatiently.

“Take me back to headquarters,” he snapped.

To the nervous, hesitant questions of the cops in the patrol car, he would make no reply. They soon lapsed into awed silence. He spoke once as the cruiser neared headquarters.

“Say nothing about this. If any member of the force lets it out, I’ll have his hide.”

The cops nodded. Whispers of the police commissioner being kidnapped had gone abroad. A few radio fans with short-wave sets had picked up scraps of the frantic broadcasts that headquarters had sent out. Newspaper men were clamoring to know if there was any foundation in the rumors. But so far the police had stalled. Events of the past week had broken down police morale. For the public to learn that the commissioner had been kidnapped would come close to causing a panic. Now, with the commissioner safely returned, the whole thing could be hushed up. It would be a secret that would never get beyond official circles.

There was a mob of eager newspaper men waiting outside headquarters. Unceremoniously, the commissioner brushed through them. Their jaws dropped when they saw him. They fell back, talking excitedly among themselves. A few bolder spirits hurled questions at him, but he answered none of them.

Back in his office, however, his manner changed. His eyes gleamed with a strange, burning light. He mopped his face with the nervous intensity of a man who has been through a terrible experience.

Inspector John Burks, head of the homicide squad, and six other inspectors were congregated in his office. Their faces had a funereal solemnity. They gazed at him like a man come back from the dead.

“Was it the same gang, chief? Did they try to bump you off — burn you?”

It was Inspector Burks who asked the questions. When he said “burn” he was not using mere underworld phraseology. There was a grimness in his tone, harsh lines in his pale, heavily browed face.

The commissioner nodded slowly. “I think so,” he said. “I escaped — I’m not saying how.”

Burks leaned forward then. His voice was a hoarse whisper, as though the things he was about to say were too terrible to go beyond the confines of that room.

“There was another robbery early this morning, chief. A cop and a special guard were killed — burned. We thought you’d got it, too.”

The others in the room nodded. They looked at each other and shifted uneasily.

The man behind the commissioner’s desk knew what was wrong with these men. He knew what accounted for the grim lines in their faces, the haggard, half-furtive expression in their eyes. It was why the commissioner’s cot was set up in headquarters. It was why the commissioner had prepared to stay there night and day.

A CRIME wave more terrible and sinister than any he remembered was facing the city. The whole police force was jumpy, fearful. The department heads were on the point of losing their morale.

“Bring me all the records,” he snapped. “I want to go over them again.”

An official police secretary went to a huge safe that contained case histories that the public had never seen. There were many volumes in the safe. A miniature rogue’s gallery. Letters of confession written by murderers who had long since paid the supreme penalty. Strange records of unusual crimes, and minutes from the latest police blotter.

The burning light in the eyes of the man behind the commissioner’s desk intensified as the records were spread before him.

Here was a factual story to make a person’s spine crawl. A series of bank and safe robberies unparalleled in the city’s history was being committed. Worse still, patrolmen, detectives, and special guards were being killed hideously whenever they got in the thieves’ way — killed by being burned alive. Six men had been murdered already. Their charred, hardly recognizable bodies had been found.

“If it hadn’t been for their shields,” muttered Burks hoarsely, “we’d never have identified Sullivan and O’Reilly tonight. Even their teeth, chief — were gone. How the hell did you escape?”

The commissioner waved the question aside as though it were unimportant. His eyes were fastened on the record books, the careful, unemotional details that had been put on the police blotter. Then he shook his head and looked up. These details told him little. Burks read the look in his eyes.

“There are no clews, chief — no fingerprints — and dead men don’t talk.”

The man behind the commissioner’s desk nodded, staring straight ahead. He seemed to be thinking, pondering. He dismissed the other inspectors and remained closeted for fifteen minutes with Burks of the homicide squad — the man closest to the ever-present specter of death.

In that time Burks went over all that the police knew, verifying each item on the records. He was a little puzzled as to why the commissioner wanted to go over these things again.

Then the door opened as a cop came in. The cop touched his cap, said: “Those news hounds! We can’t get rid of ’em. The desk phone rings every minute, and there’s a pack of ’em outside. They want to know if you were kidnapped and how you got away.”

The commissioner nodded. His face hardened.

“The less we tell them,” he said, “the more curious they’ll get. We’ll have to hand out something. Who’s in the mob?”

“A guy from every sheet in town — and that skirt from the Herald—Miss Dale. She’s the worst of the lot.”

“Betty Dale!” The commissioner uttered the name slowly. His face changed. A strange look came into his eyes. “Show her in,” he said. “I’ll talk to her alone.”

IT was known that Betty Dale of the Herald had a drag at headquarters. Her father had been a police captain slain by underworld bullets. As a kid she had roller skated in the very shadow of the precinct houses, sharing her candy and apples with the cops. She had been a favorite and a pet. Now she had grown to young womanhood. The commissioner’s announcement that he would see her caused no comment. The other reporters made friendly jibes at her “wire-pulling” ability.

The commissioner dismissed Burks, sat back behind his desk, watched the door. High heels clicked in the stone corridor outside. The girl who came into his office had the blue eyes and the golden hair of a stage beauty. But her manner was briskly efficient. There was a worried frown between her arched brows. A pencil was poised in her slim fingers. She spoke with professional abruptness.

“Thanks, commissioner, for seeing me. People are wondering whether there’s anything in the rumor that you were kidnapped. My paper would like a story.”

For a long moment the man behind the commissioner’s desk eyed Betty Dale. His gaze appraised her from her slim feet to the top of her head where her wealth of golden hair had the sheen of imprisoned sunshine. Smartly dressed as always, Betty Dale was a picture of loveliness. Far back in the eyes of the man who looked at her was something deeper and more personal than mere admiration. But his first words were startling, making the girl stare at him questioningly.

“The stage is set,” he said. “The second act is about to begin.”

The sentence seemed strange, meaningless. A slow pallor overspread Betty Dale’s face.

The commissioner smiled, rose, and shut the door tightly.

“Come closer,” he said. “There is a fox in the lion’s den.”

Betty Dale began to tremble now. The man’s words seemed to have a strange effect on her. She was staring at him as though she were looking at a ghost. Quietly he tore a corner from a small pad. As quietly he wrote something on it — the single letter “X.” He held it up for Betty Dale to see, then dropped it in an ash tray and touched a match to it. As the smoke from it curled up, the girl spoke huskily.

“You!” she said. “It can’t be!”

The man behind the commissioner’s desk nodded somberly.

“To gamble is to live,” he said. “And when death is close, men will gamble at long odds.”

“But the real commissioner?” she asked. “Where is he?”

“Safe and sound in the fox’s den.”

Color began to come back to Betty Dale’s face. Slowly she got hold of herself, stopped trembling. They were old friends, these two, Betty Dale and Secret Agent “X.”

A hundred times he had fooled her with his disguises, but never in so startling and daring a manner as this. To come and find him sitting behind the desk of the city’s police commissioner made Betty Dale feel that she could hardly trust her own senses. She gave one short, shaky laugh, relieving her nervous tenseness.

Agent “X” thought she had never looked so lovely. In that moment, when she was off guard completely, it seemed that there was a light in her eyes answering that subtle something in his.

There was a reason for the emotion that Betty Dale betrayed. This man, whatever his real identity might be, had been a friend of her father’s, the police captain slain by murderers’ bullets. The rest of the world might consider Agent “X” a desperate criminal, but she knew otherwise. She knew that even behind this daring thing he had done tonight lay some deeply hidden plan for combating crime.

She admired his unshakable nerve, sensed the strange magnetism of the man, and felt drawn to him so strongly that she sometimes had to hide her own emotions. She had vowed that she would never let sentiment interfere with his strange, important work. Now, with a ghastly crisis threatening the city, she disciplined herself more strictly than ever. When he took her hand, she let him hold it only a minute, then drew it away.

“What shall I tell the other reporters?” she asked.

“Tell them you’ve seen the commissioner,” he said. “Tell them he looks all right, and that he speaks lightly of the report that he was kidnapped.”

BETTY DALE bent her blonde head, made notes on her pad. Whatever Secret Agent “X” said she would do to the letter. She trusted him, respected him, as she did no other man alive.

“Au revoir,” she said; then, raising her voice as someone moved in the corridor outside, she added, “Thank you for releasing a story, commissioner. I’ll quash any reports that you were kidnapped.”

For a moment her eyes met the strange man’s behind the desk. Then she stepped back and her slim, shapely figure vanished through the door. No one could want a more loyal ally than Betty Dale.

But Agent “X’s” eyes were harsh. She had helped him many times, but he would not ask her to take part in the sinister struggle now in hand. It was too dangerous, too terrible. A moment later his eyes grew harsher still. For Inspector Burks of the homicide squad reappeared suddenly in the doorway. A gray pallor had overspread Burks’s face. His voice shook with emotion.

“A call has just come in,” he rasped. “There’s been another slaughter, chief, and the worst so far. An attempt was made to rob the Merchants’ and Manufacturers’ Bank. Four men have been killed! It’s the same gang that kidnapped you.”

For a moment there was breathless silence. Then Secret Agent “X” stood up, his fist clenched on the desk. It was strangely, terribly ironic that Burks should be telling him this. The blackbrowed inspector who stood before him was one of the Agent’s most unrelenting enemies.

Inspector Burks caught his breath, gulped, and spoke hoarsely.

“I’m on my way now, commissioner. I’m going to look things over — and get those damned killers if it costs me my life.”

Secret Agent “X” stepped from behind his desk, reaching for the commissioner’s coat and hat.

“I’ll go with you,” he said, and his words were like the crack of a whip.

In silence the two men descended to the street below. The desk sergeant nodded, stared wide-eyed. Two detectives watched their departure grimly.

A closed headquarters car was already at the curb, the inspector’s chauffeur at the wheel. Both men stepped into it — the car sped away with a whine of smoothly meshed gears.

Lolling back on the comfortable seat, Secret Agent “X” wondered if their investigation of the crime would bring results. His trip to headquarters, his kidnapping of the commissioner, had been futile. The police, though they had kept all details to themselves, were far from any solution of these terrible murders.

Agent “X” straightened suddenly. His eye had caught sight of something in the chauffeur’s windshield mirror. He turned his head, looked out the rear window. Then his elbow nudged Inspector Burks’s side.

“We’re being followed,” he said.

“What!” Burks’s head turned, too. For seconds he stared back in amazed silence.

They had turned a corner, left headquarters behind. Back of them, appearing as though by magic, a low-slung dark roadster built like a racing car was following. The sides of the car were high. A black hood swept down to the narrow windshield in front. Side curtains made its interior dark. But Secret Agent “X” caught sight of light glittering on goggles. For an instant he looked into an expressionless, masklike face — a face that was like a crustacean monstrosity, distorted and made inhuman by some sort of weird helmet.

His fingers clenched over Inspector Burks’s wrist. He was about to say something, but his words died in his throat.

One of the side curtains of the car behind bellied outward. The helmeted head appeared around the windshield’s side. And, in the hands of the man whose features were hidden, Agent “X” saw the gleaming muzzle of some sort of weapon.

Inspector Burks shouted a hoarse warning, but his words were lost in the horror of what followed.

No report came from the weapon in the man’s hand. But a blinding, white-hot jet of fire suddenly sprayed from it. It was like a ghastly will-o’-the-wisp, a torch of living, consuming flame suspended apparently in space. With a hiss of scorching enamel and burning fabric, the flame leaped forward and struck the back of Burks’s car.

Agent “X” could feel the heat inside. A giant acetylene torch seemed to have been turned on them. He heard the snap of breaking glass, saw a tongue of flame leap over their heads.

The driver of the police car, looking back, glimpsed the bright ball of fire, too. He gave a cry of fear, tried to wrench the car into a side street.

The vehicle turned in its own length and the horrible jet of fire traveled along its side like water from the nozzle of a hose.

The full force of it, sizzling, intensified, touched the window by the driver’s seat. The glass melted and ran down in a hissing liquid stream. The tongue of flame licked inward in a blasting wave of heat like breath from the mouth of an inferno.

Before their horrified eyes the driver, with a shriek of fear dying on his lips, wilted in his seat. His head became a mass of ghastly, licking flames. His features disintegrated. His clothing caught fire, and, with a jarring crash, the car, with dead hands on the wheel, plunged across the curb toward a building.

Chapter IV

AGENT “X” felt sickened, paralyzed. The stench and reek of scorching flesh was in his nostrils. Horror pressed upon him like a black, smothering wave. Then something hissed beside him. The flame was probing for the rear of the car again.

Like a coiled spring unsnapped, Agent “X” came to life. He reached forward, grasped the car’s wheel, gave it a twist, and slewed the front tires around just as the car struck. It saved them from the full, shattering concussion of a head-on crash.

The big vehicle hit at an angle and scraped ahead to a shuddering stop with its radiator cap almost in a doorway.

Secret Agent “X” was hurled against the front seat, almost on top of the dead chauffeur. Inspector Burks thudded against his back, fell to the car’s floor. The inspector was swearing fiercely, trying to pull himself up. The white-hot searing flame of the burning death behind them was seeking them out again.

Agent “X” heard a shrill squeal of brakes as the murder car sought to check its speed. It stopped, began to back, and the snout of the mystery weapon swung around in a murderous arc. The flame hissed brightly, relentlessly, again.

In one and the same movement then, Agent “X” thrust open the car’s door that was on the side facing the building and leaped out. Grabbing Burks by the arm he drew the man unceremoniously after him. A space of five feet separated the front of the car from the building’s door.

The men in the murder roadster were playing the flame over that space, preventing any escape in that direction. Agent “X” with the inspector beside him crouched behind the big metal body of the car. The death flame licked against the car’s opposite side, played a hissing, horrible tune of doom. The wall of the car became red-hot. The fabric began to smoke. Another window gave way and the flames licked through toward them.

The searing torch of destruction was searching them out. The inspector had drawn a police automatic from his pocket. Cursing like a maniac, he began firing back toward the murder car, his bullets going wild. One side of his coat was scorched. His eyes were bloodshot. As the flame ate through the window on their side, Agent “X” drew him down behind the protection of the car’s big engine. The tongue of searing death whistled above their heads now. The space between the car and the building’s side was getting as hot as a furnace. The horrible threat of being roasted alive faced them.

There came a shriek like a thousand howling banshees. The flame’s heat had ignited the car’s gas tank. The screw cap had blown and a jet of burning gas was whistling through the vent, mingling with the flame of the death torch in the hands of the murderer.

For a moment the night wind whisked a curtain of dense vapor along the car’s side. And in that moment Agent “X” pulled Inspector Burks toward the doorway. He literally hurled the man ahead, flinging himself after, running the awful gauntlet of flaming death.

The murderers in the car couldn’t see them. Crouched back in the doorway Agent “X” glimpsed the goggled and helmeted killer leaning far out, playing the death flame on the smoking, crackling police car. Then the car’s gasoline tank let go, as the pressure became too great for its metal walls to stand.

The whole rear of the car ripped open. The murder torch licked in and around it until the car became a flaming inferno, a funeral pyre for the dead driver.

The hideous goggled head of the killer withdrew. With a scream of gears the roadster leaped ahead and tore up the street out of sight.

Windows on all sides were opening now. Excited people were screaming. The flames of the burning car were threatening to fire the building against which it lay, as sprayed gasoline ignited.

Burks, with the pallor of a man who has looked into the face of hideous death, drew a shaking hand across his face.

The building in the doorway of which they had taken refuge was a cheap rooming house. Terrified people were opening the inner door: a fat woman in a bathrobe, a man with hair standing on end, two gangling youths. Agent “X” pushed them back.

“A phone! Quick!” he cried.

The fat man made ineffectual gestures. “X” ran on till he saw a coin box phone against the wall. In a moment he was dialing the operator, turning in an alarm. There would be fire engines here presently and cars from headquarters.

He heard the first of the engines from a nearby station roaring up the street. The chassis of the burning police car was glowing red hot. All fabric and upholstery were gone. The driver in the front seat was hardly visible, but there was still the nauseating, horrible odor of burning flesh in the air. Agent “X” had seen many men die, but seldom with such sudden stark brutality as this.

A POLICE cruiser whirled up the block. Hand extinguishers from the red fire truck were beginning to quench the blaze as the crowd gathered. Bedlam reigned in the street. But Agent “X,” in the role of the commissioner, spoke quietly.

“We were on our way to look at a murder, inspector,” he said. “Let’s get going.”

Inspector Burks nodded. There was nothing they could do here. The driver of the police car had long since been beyond their help. Other cruisers were arriving and a squad car full of detectives. Agent “X” commandeered it, leaving two cops in charge of the burned and wrecked sedan. Three radio cruisers followed them as escort. Inspector Burks, still trembling, sat back breathing heavily.

“They almost got us,” he croaked. “If it hadn’t been for you, commissioner—”

He did not finish, but a strange, harsh smile played over the lips of Secret Agent “X.” What would Burks say if he knew that the man whose cool-headedness had saved him from that hissing murder flame was the person he had hunted and tried to trap as a criminal?

“We know now how the killers do it,” “X” said. “That was some sort of flame-thrower. Flammenwerfer. But not the kind the Germans used in the Bois d’Avocourt or those of the British on the Somme in ’18. This is something new. It is murder modernized, inspector!”

For a moment a question flashed in the bloodshot, frightened eyes of Inspector Burks. He looked at the commissioner sharply, wondering apparently how the commissioner could give offhand dates like that. Secret Agent “X” had almost made a slip.

“I suspected it from the first,” he said, quietly. “I’ve been doing a little research.” The man of a thousand faces was on his guard again. Burks must not know that every weapon of modern warfare was familiar to him.

They plunged on in silence, shaken, sickened, by what they had been through.

THE building in which the Merchants’ and Manufacturers’ Bank was housed took up half a city block. It was a bulky, old-fashioned flat-roofed skyscraper of twenty stories. The street outside was filled with curious, morbid people now. Ropes had been stretched across the bank’s front by the police, holding the crowd back. A dozen or more cars were parked close by.

The police lines opened instantly to let Inspector Burks and the man impersonating Commissioner Foster through.

But Agent “X’s” pulses were hammering excitedly. Every faculty was alert. He knew that in coming here he was taking a dangerous chance. His disguise might be perfect, but he didn’t know the commissioner’s inner thoughts, or all the people with whom he associated. He might make the wrong answers, might arouse suspicion. He planned to get away as soon as possible.

For an instant he glanced at the outside of the bank. It was one of the city’s smaller financial institutions, a private bank controlled by five partners. Three of these partners, Burks had said, had been slain. Honer, Osterhout, and Davis were their names. Their bodies were still inside, where, surprised in late conference by the raiders, they had met death under the blast of the terrible Flammenwerfer.

But it was the body of the special bank guard in the corridor outside that Agent “X” first saw. He turned his eyes away from the charred, grotesquely sprawled figure. Except for the man’s blackened badge, it might have been impossible to identify him. Even the bones of his face and his teeth had been eaten away by the withering heat of the killer’s torch.

The bodies of the three bankers, John Honer, Eric Osterhout, and Jerome Davis, in the business room behind the cashiers’ cages, were in hardly better shape.

Detectives were checking up, making identification from the blackened, heat-corroded watches, cuff links, and cigarette cases that lay beside the corpses in the piles of grayish ashes that had once been clothing.

Two of the dead men had been burned on both sides of their bodies, reduced to unrecognizable carcasses. The third, Davis, had received the withering flame on his face and the front of his body only. His features were ghastly but still recognizable.

The Agent studied the position and condition of the corpses for tense moments. Then he looked at the huge vault in the bank’s rear. Marks of cutting tools showed around the edges of the locks. It had withstood the onslaught of the raiders’ attack, justifying the faith of its builders.

“Has the vault been opened?” he asked. “Is everything all right?”

“We don’t know, sir. We’re waiting for Marsh and von Blund, the other partners. They’re on their way.”

Burks, standing at the Secret Agent’s side, shot an abrupt question.

“Were there any employees besides the bank guard around?”

Mathers nodded.

“I talked to von Blund on the phone, called him right after I got here. A cashier and one of the bookkeepers were working overtime, too.”

Inspector Burks face grew hard.

“Get their names — find them,” he barked.

“I’ll have to wait, sir, until—”

Mathers didn’t finish, for the police lines were opening to let two well-dressed men through.

“That’s them now,” said Mathers. “They’ll give us the dope.”

Marsh and von Blund, the surviving partners, gasped with horror as they passed the body of the murdered bank guard. How much had Sergeant Mathers told them? Were they prepared for the added shock that awaited them? Evidently not, for von Blund, the older of the two, a blond, stern-faced man in his early forties, stood speechless at the door of the business room. He swayed, leaned against the wall, his eyes starting from his head. Marsh, shorter, stockier, with the poker face of a typical financier, stood with hands clenched at his sides.

It was von Blund who spoke first.

“Eric!” he gasped. “My God, Eric!”

AGENT “X” saw the man turn his eyes away from that unsightly relic on the floor which had been his friend and partner, Eric Osterhout.

“We went through the war together,” muttered von Blund brokenly. “Even that couldn’t separate us. But now—” He clenched his fist. “If the law doesn’t get those fiends, so help me, I will!”

Agent “X” walked close to the body of Eric Osterhout. Detectives were pulling something from the ashes — a tiny metal pin with the crossed wings of a flyer on it. Agent “X” took it in his palm, stared at it. He spoke quietly to von Blund.

“Your friend must have gone in for aviation,” he said.

Von Blund nodded. “In war and peace,” he answered, “it was one of his hobbies.”

Inspector Burks edged up impatiently and shot another question. “Mathers tells me there were two employees of the bank here with your partners. Where are they?”

For a moment von Blund and Marsh looked at each other, then they stared at the inspector.

“Haven’t you seen them?” asked von Blund harshly.

“No.”

With quick steps the banker crossed to a desk behind the cashiers’ cages. His fingers trembled as he drew out a book giving a list of employees’ names and addresses.

“Spencer and Cox,” he said. “One was our head cashier — the other was in the bookkeeping department.”

“They’ve disappeared,” snapped Burks. “That’s evident.”

“Call up their homes,” said von Blund. “It isn’t like them to run away unless—”

“Unless,” echoed Burks, “they had something to do with the job that was pulled tonight.”

Secret Agent “X” spoke then, pointing to the vault.

“It doesn’t seem likely. The cashier must have known how to open the vault. If he—”

But Marsh, the stocky partner, spoke quickly.

“Only the five of us knew how to do that,” he said. “But maybe Spencer thought he could. Maybe that was why—”

“It might be a good idea to look inside,” said Agent “X.” “Perhaps they got in after all — and closed the vault behind them.”

Von Blund nodded. But a quick examination of the vault’s interior, after he and Marsh had opened the great door, showed that nothing had been touched.

“Thank God for that,” said von Blund fervently. “Our depositors won’t suffer, anyway!”

But Inspector Burks voiced a sinister thought that was in the Secret Agent’s mind also.

“The raiders didn’t make the grade this time, but what will stop them from trying again?”

Von Blund clenched his fist.

“We’ll land them in hell if they do. I’ll hire a squad of special guards. We’ll have machine guns posted. Eric, John, and Jerry lost their lives to protect the funds entrusted to them. We’ll see that they didn’t die for nothing.”

There was a quaver in von Blund’s voice, but Agent “X” wondered if any stratagem an honest man could devise could checkmate the fiends who put men to death with hissing flame.

SERGEANT MATHERS came back with a frown on his face.

“I’ve called up the homes of Spencer and Cox,” he said. “They haven’t returned, but they were here tonight, all right. It looks, Mr. von Blund, as if—”

“I won’t believe it,” cried von Blund. “They’ve been with us for years. They were honest, I tell you. Perhaps those fiends kidnapped them.”

Inspector Burks, cynical veteran of a thousand homicide cases, spoke grimly.

“Sentiment is a fine thing, von Blund. But don’t let it get the best of your reason. Spencer and Cox were probably bribed by the murderers to make things easy. When the raid failed, when they couldn’t open the vault, they made a get-away. I’ll start a dragnet. I’ll have every outgoing train and boat searched and have all roads watched.”

The disappearance of Spencer and Cox added further complications to the chain of ghastly murders. Had the cashier and bookkeeper of the Merchants’ and Manufacturers’ Bank been mixed up in the raids of the flaming torch killers all the time? Or had a bribe or some hidden, sinister threat made the two employees of the bank betray their trust? Agent “X” pondered this.

“The D.A.’s on his way, too,” said Burks harshly. “The public’s been riding him, and he’s got it in for you, commissioner! You know the row you and he had last week!”

Agent “X” nodded, but his eyes grew suddenly bright. What row did the commissioner have with the district attorney? That was something the blotter at headquarters hadn’t indicated. It was time he left before he made some slip in the presence of the alert D.A.

“I’ve got to get back to headquarters,” he said abruptly. “There’s another angle of this thing I’m working on.”

If Inspector Burks felt the commissioner’s sudden decision to leave was odd he didn’t indicate it. Perhaps he thought the commissioner wanted to avoid unpleasant contact with the D.A. This was the case, but not for the reasons Inspector Burks might have assumed.

The inspector accompanied Agent “X” to the door and mapped out his campaign for trapping the two runaway bank employees.

“If we can catch ’em,” he said, “we’ll sweat ’em till we find who the guys are that hired ’em. I don’t believe they pulled this job alone.”

At the door of the bank, Inspector Burks suddenly swore and stabbed a finger toward the street.

“Look! There’s that nut, Banton,” he said, “trying to get in and pull a snoop act again. He forgets he ain’t with us any more and that we don’t let four-flushing agency dicks sit in if we can help it.”

Agent “X” stiffened. He had never heard of Banton. The inspector spoke as though here were a character well known to the commissioner. “X” turned his head, saw a red-faced, gross-bodied man trying to shove through the police lines, as a cop forcefully restrained him. When “X” opened the door of the bank he heard Banton’s angry voice.

“I got offices in this building, I tell you,” the man was saying. “You can’t keep a guy away from his own place.”

As Banton caught sight of Secret Agent “X,” a look of sneering familiarity overspread his face.

“Be a sport, commish! Let a guy look around. Just because you kicked me off the force don’t mean I’m poison. There’s a reward out for these killers. I can use dough as well as the next person — and your gang ain’t showin’ up so smart!”

There was a bitter slur in that last phrase that Agent “X” caught. The finely tuned mechanism of his memory was working now. Banton! The name stirred recollections. There had been a big police shake-up, a cleaning out of grafters a few years ago. Banton was the name of one of the lieutenants whose resignation had been “gratefully received.” “Kicked off the force,” Banton had said.

AGENT “X” in the role of the commissioner walked toward Banton. The man’s lips curled back from stained teeth and he made another slurring remark.

“A swell bunch of sleuths you got, commish! I been in business myself for nearly two years, and I ain’t never been licked on a case yet. That’s why I want to look in on this. You can’t keep me out either, commish. I got diggin’s right in the bank building.”

Agent “X,” acting as the commissioner, waved his hand.

“Let him look around,” he said magnanimously.

“Thanks, thanks,” sneered Banton. “Big-hearted of you — commish! You always was a square guy, weren’t you?”

The eyes of Banton gleamed with bitterness and hatred, and Agent “X” went on his way wondering. Police were being slain, burned alive. Banton, kicked off the force on a graft charge and now in the detective business for himself, would be worth investigating. Was it possible that bitterness and a deflated ego could account for the brutality and ruthlessness of these strange crimes?

Speeding to headquarters in an official car, Agent “X” tensely pondered these things. He would stay in headquarters just long enough to look up the records of Banton.

Back in the commissioner’s office he started to take off his hat and coat, then paused. Following his entrance there came a sudden sound of excitement downstairs. He heard an elevator click open. Then there were louder sounds in the corridor outside — the noise of pounding, running feet.

Suddenly the door of the commissioner’s office burst open and an angry, disheveled man stood in the threshold — a man with a shabby overcoat wrapped around his tall, sparse body.

Police Commissioner Foster!

Speechless for a moment, Agent “X” faced the man he had impersonated. He realized in that instant that the weak-kneed gangsters he had hired had got cold feet — let their prisoner go. And, as he stood collecting his thoughts, the commissioner raised a trembling finger and pointed toward him.

“Arrest that man,” he said. “He’s a criminal and an imposter.”

Chapter V

A HALF-DOZEN detectives crowded in the doorway behind the commissioner. All eyes were focused on Secret Agent “X.” The room became charged with a tension that was almost electric.

The Agent met the commissioner’s accusing gaze calmly. By no movement or gesture did he betray any indication of nervousness. But he fully sensed what a desperate spot he was in.

Since he worked always beyond the law he could not expect any official support if his identity was discovered. He would be exposed and convicted as an imposter and dangerous plotter, convicted probably as an accomplice of the killers who were terrorizing the police. But his voice was as steady as his manner.

“This is absurd!” he said. “Have you any documentary proof to back up your claims? You must be a madman!”

“Madman!” The commissioner’s face became a mottled, almost apoplectic red. He turned, made gestures toward his men. “Arrest him, I say. He’s the criminal who kidnapped me.”

Agent “X” drew the commissioner’s wallet and papers from his pocket, spread them out on the desk in front of him. With a grim smile on his lips he pointed to them.

“Here are papers which give the lie to your wild claim.”

The commissioner gritted his teeth in fury.

“You stole them,” he cried harshly. “You stole my clothes and my papers. You are an imposter and you know it!”

“Is that so? Can you prove it?”

For a moment a baffled, helpless look crossed the commissioner’s face. Then his chin shot forward and his eyes snapped fiercely.

“Yes,” he barked, “I can prove it! When I came into office I ordered every patrolman, detectives, and department head fingerprinted. Prints were taken of every member of the city’s police including the commissioner. The records are right here in this building. Let them be brought and I’ll match prints with you. We’ll see then who’s the imposter.”

A brief, bleak smile came into Agent “X’s” eyes. In the person of the commissioner he had a worthy adversary. The man was alert, on the job. Fingerprints didn’t lie. Inside five minutes the Secret Agent would be shown up and trapped as an imposter.

But he made a quick gesture, gave an imperious order.

“Get the fingerprints in file F,” he said. “Tell Deputy-Inspector Taylor or one of his assistants to come to my office at once.”

He spoke with such assurance, seemed so familiar with the routine of headquarters, that the detectives in the door wavered in uncertainty. One of them went to get the fingerprint files. The commissioner, clutching his shabby coat about him, glared fiercely at the man who had usurped his office and duties.

Secret Agent “X” seemed not to have a care or worry in the world. He dipped his fingers into an inside coat pocket, drew out a cigar, and skinned the cellophane wrapper from it. For a moment he ran it under his nose, sniffing the fragrant weed in the manner of a connoisseur. He bit off one end, placed the cigar between his lips, and lit it.

For a second or two he stood puffing, staring back at the furious commissioner with round, quizzical eyes. Then suddenly, as though he had gone through some inner process of counting, he took the cigar from his mouth and tossed it on the floor.

The detectives stared wide-eyed. Police Commissioner Foster, sensing some sort of trick, opened his mouth to give a warning, but he was too late.

The wrapper of the cigar tossed on the floor by Agent “X” burst apart like a firecracker. A blinding cloud of dense white vapor shot into all parts of the room, billowing out into the corridor.

Just before it reached him Agent “X” took a deep breath and marked the position of the door. As the dense vapor cut off vision as effectually as a white curtain, he leaped around the desk and crossed the room in four quick strides.

The detectives had stepped away from the door. Agent “X” brushed through them and out into the corridor. The smoke given off by the cigar was the same as that used by sky writers. A draft had drawn it along the corridor.

WITH desperate speed Secret Agent “X” leaped along the hallway and down the stairs. He had made himself familiar with the layout of headquarters. When he reached the landing below, he turned left and dashed along a lower hallway to a side exit. A cop barred the door, saw the commissioner, and stepped back. The commissioner nodded and passed out into the night.

With quick, cautious steps he skirted the side of the building, and approached the front. A vague hubbub sounded above him. He looked out into the street. The plain-clothes men stationed outside headquarters had been attracted by the uproar inside. They were disappearing into the vestibule.

Agent “X” turned and walked rapidly away down the block. It was late. The street was deserted. He heard a car coming and ducked into an alley between two buildings. Then he moved out and ran on. Two blocks away he crouched for a moment in the semigloom of an unlighted stoop and went over his face with tense, skilled fingers.

The black mustache and most of the characteristics of Commissioner Foster disappeared. Plates plucked from his nostrils changed the contour of his nose. When he reappeared he was a different person. But he still had the commissioner’s clothing on. He walked rapidly away, hailed a taxi, and drove to the neighborhood of one of his several hideouts.

Alone, with a portable make-up box before him, he made a careful change of facial disguise, removing the last traces of those things which had made him resemble Commissioner Foster.

He slipped into a new suit, a pepper and salt, loose-fitting tweed. He drew on a slouch hat and a raglan coat. A notebook pencil and Associated Press card completed his disguise. As an inquiring newspaper reporter many channels of investigation would be open to him.

The Agent’s work was only beginning. His desperate visit to headquarters in the role of Commissioner Foster had led to an impasse. In this sinister business of the Flammenwerfer murders the police were working in a black and ghastly fog of mystery.

His eyes were hard and bright as he descended into the street again. One name and one face still remained in his mind. Banton! In a case where clews seemed lacking it was the Agent’s method to leave no stone unturned. Banton was worth investigating.

He took a taxi to within two blocks of the bank, then walked forward. Police still held the tense-faced crowd back. The crowd had thinned, but those who hung on were the seasoned and morbid thrill-searchers who would stay all night if necessary.

Agent “X” saw the tall, familiar form of the medical examiner. The official doctor had completed his work, checked up on the charred bodies. A police ambulance was backed up to the door of the bank. Four men with a stretcher between them were moving toward the ambulance. The crowd shuddered, craning collective necks. But the still figure on the stretcher was mercifully covered. The victims of hideous murder were being removed.

Agent “X,” displaying his press card, broke through the police lines. But one of Inspector Burks’s men barred him at the door of the bank, refusing admittance.

“There’s been enough snooping around here tonight,” he said harshly. “Orders from the chief! You gotta keep out.”

THE sound of angry voices came from inside the bank. Two detectives walked forward roughly propelling a third man between them.

Agent “X” stared intently. The third man had a red face, thick lips, and a fat body. But his eyes were small, shrewd. It was Banton, the ex-police lieutenant. The two detectives shoved him forcefully out. Banton was complaining bitterly.

“The commish himself told me I could look around,” he said.

“He didn’t say you could poke into all the bank’s private papers,” snarled one of the dicks. “Give you an inch and you take a mile. Get the hell out and stay out.”

There was an ugly gleam in Banton’s eyes. He made one of his jeering, sneering remarks.

“Smart boys, eh!” he said. “The whole lousy force will be wiped out before any of you find who the killers are. But it won’t hurt the city if a lot of dumb clucks are cleaned up.”

“What’s that?” said one of the detectives.

“I said you could go to blazes,” lied Banton.

He stood mopping his face, glaring toward the receding backs of the two detectives who had ejected him. Secret Agent “X” moved up, displaying his press card.

“They won’t let me in at all, buddy,” he said. “Give us the low-down on what’s happened.”

Banton rolled a belligerent eye.

“Go to hell. Find out for yourself.”

Agent “X’s” voice was wheedling.

“Give a guy a break,” he said. “I just got here — couldn’t get away from the office sooner. Who do the dicks suspect?”

Banton’s lip curled contemptuously. “Ask ’em,” he said. “They’re hot stuff — always on the inside track, always have the right dope. They’ll give you the murderer’s address and phone number. Then you can go around and get a signed story.”

With a raucous, sarcastic laugh Banton flung off. He passed through the police lines with a jeering word to a cop. Agent “X” watched him a moment, then casually turned and followed. He edged to the outside of the crowd, kept Banton in sight.

The man swung around the block and approached the bank building from the other side. There was a side entrance there, leading up to the scores of office floors above.

Banton, lumbering like a huge, ill-tempered bear, went into the building. His office could evidently be reached from this side, too. Since the police had barricaded the front, he had come around this way.

When Banton had disappeared Secret Agent “X” increased the speed of his steps. He moved out of the shadows, crossed the street. An instant more, and he had slipped into the bank building, following the belligerent ex-police lieutenant.

Chapter VI

THERE was one all-night elevator still running, operated by the janitor in the basement. This could be summoned by a bell. The door of it was just clicking shut. Banton was ascending.

Agent “X” walked back along the corridor and looked at the directory board. Searching under “B” he found the name “Banton. Detective Agency.” The suite was No. 428.

With quick decision he turned and made for the stairway. Silently and swiftly he moved upward.

When he reached the fourth floor, the broad, lumbering form of Agency Detective George Banton was just disappearing down a corridor that swung at right angles. He did not look back. He didn’t know that he was being followed. Agent “X,” master of shadowing, seemed almost a part of the dark wall as he proceeded after the ex-police lieutenant.

When he came to the angle of the corridor he peered around it. Banton was thrusting a key in a lock, opening his office. He disappeared inside, snapped on a switch, and shut the door. Through the frosted plate glass Secret Agent “X” saw the man’s shadow for a moment and saw the large gilt lettering that proclaimed the man’s profession to the world.

He wondered if Banton was what he appeared to be. As a police lieutenant Banton’s record had been unenviable. He had indulged openly in graft and had been asked to resign from the force. Some private detectives made a precarious living on the ragged edge of the law. They had been known to frame innocent people, obtain false testimony, and perjure themselves on the witness stand. Banton looked like the type who would know every trick by which a private dick might turn a dishonest penny.

Agent “X” was about to enter the Banton Agency to see why its owner was up so late. But suddenly he stopped. Far down the end of the corridor something diverted his attention.

There was an open transom above a closed office door. Through this transom an odd light showed.

The light had a strange quality to it. It was blue and wavering like the glow from a spark gap. It sent weird reflections along the sides of the corridor, cast flickering shadows around the edge of the transom.

Agent “X” moved toward it wonderingly. As he came close he could hear a faint crackling sound. His body tensed. Then another sound came above the lightning-like crackling. It was the whir of some sort of machinery. This stirred his curiosity even more.

The room at the end of the corridor couldn’t be one of the building’s power stations. The name card on the door said: “A. J. Darlington.” It was obviously a private office.

On a night when the bank below had been attacked, when four men had met horrible deaths, anyone working as late as this in the building was worth investigating. Secret Agent “X” pressed the button beside A. J. Darlington’s door.

The whir of the machinery inside began to diminish. The crackling blue light in the transom above the Agent’s head got dimmer and faded away. Only the glow of an electric bulb showed. Footsteps sounded inside.

The door was opened and a head thrust out. Agent “X” was prepared for the unusual, but he tensed as he stared at the figure which stood just inside the threshold.

The man would have been arresting anywhere. He was tall, white-haired, and gaunt, with a leathery face and deep-set eyes. Clad in a stained smock, with his sleeves rolled up over skinny, hairy arms, he stared at Agent “X” questioningly.

“What do you want?” he demanded.

His tone was gruff, irritable, the tone of a man who wishes privacy and resents interference. The word “crank” was written all over him — in the unpleasant harshness of his voice, in the peevish, discontented lines of his face. And especially in the antagonistic light in his eyes.

Agent “X” cleared his throat, smiled. He took his press card from his pocket, thrust it under Darlington’s nose.

“I’d like to ask you a few questions, Mr. Darlington.”

As he spoke Agent “X” edged forward, his sharp eyes stabbing into the room. Then he tensed inwardly. Beyond Darlington, through an open door, he glimpsed a completely equipped laboratory, filled with expensive scientific paraphernalia. There were glass retorts for distilling chemicals, strange-shaped jars, metal cylinders, static electrical machines, and a large, complex optical instrument on a tripod. Each object registered in his lightning-fast brain, and roughly he estimated that they must be worth thousands of dollars.

BUT the gaunt man before him drew the door closer and shook his head violently, suspicion in his eyes.

“I’ve nothing to say to you newspaper men. When I’m ready to talk, I’ll talk. You can’t pry into my affairs and misrepresent me. You’re all too dumb to understand what my studies into the nature and action of light may mean. Good-night, sir, and don’t bother me again.”

Darlington tried to close the door, but Agent “X” deftly thrust a foot into it. He pressed forward, shoving the tall man back. Darlington’s eyes blazed angrily. But Agent “X” stood his ground.

“Just a few questions,” he insisted. “I believe you’re going to be disturbed more than once tonight.”

“What do you mean, young man?”

Agent “X” eyed Darlington steadily. “Perhaps it will interest you to know that an attempt was made to rob the Merchants’ and Manufacturers’ Bank downstairs. Four men were murdered.”

Darlington skinned his lips back from long, rodent-like teeth and made annoyed gestures with his hands.

“A bank robbed! What is that to me? It is the gold of the sunlight I’m interested in — gold that travels at the incredible speed of one hundred and eighty-six thousand miles a second. The laws of infinite space — the mystery of electrons billions of miles away — are what I am concerned with.”

“Murder can’t be dismissed,” said Agent “X.” “Four men were killed, I tell you — burned alive in a room less than a hundred feet below you.”

Darlington raised his eyebrows. “Shocking!” he snapped. “But no concern of mine. If men would forget their mundane troubles and contemplate infinity there would be less crime. The life of man is brief — and according to Mr. Einstein’s law of relativity—”

Agent “X” cut him short. “At what time did you come into this building tonight? Answer me that, Mr. Darlington.”

Their eyes clashed for a moment, then Darlington spoke sulkily.

“I always come at eight — after the clammering crowd has gone. I come then so that I can have peace and quiet in which to work.”

“Doesn’t murder mean anything to you?”

“A sordid sociological phenomenon,” said Darlington pompously. “Something for the criminologists to deal with. My labors lie in the field of abstract science.”

“You saw nothing unusual then when you entered this building tonight?”

“There was a light in the bank. I saw that. These are hard times for the fools who slave their silly lives away in the marts of gold. When I saw the lights in the bank’s windows I recalled that magnificent proverb of Marcus Aurelius: ‘He who gazes on the farthest star learns more than—’ ”

Agent “X” interrupted the strange man’s discourse again. “I can quote you as saying then that you saw the lights in the bank at eight o’clock?”

“You can quote me as saying nothing, young man. And now, if you’ll please leave, we’ll terminate this fruitless and unpleasant interview.”

Agent “X” made no move to go, and Darlington suddenly bent his angular body and leaped forward. Seizing Agent “X” by the shoulders he shoved him through the door in an effective “bum’s rush.” The tall crank was amazingly spry and powerful for all his white hair.

Agent “X” tried suddenly to check himself. For, as the door opened and Darlington thrust him out, he saw two men close at the end of the corridor. One was Sergeant Mathers of the homicide squad. The other was a detective from the same department. Before he could stop he slammed into them, nearly knocking the breath from their bodies.

Chapter VII

IF AGENT “X” hadn’t clutched Mathers, the mastiff-faced detective would have fallen. He gasped, swore, and banged against the wall.

“What the hell!” he growled.

Agent “X” heard the door of Darlington’s office close with a bang. A harsh, mocking laugh floated through the transom overhead.

“What’s going on here?” barked Mathers pulling himself together, recovering his dignity.

Secret Agent “X” drew out his press card again.

“I was looking around, chief. I saw a funny light in that office and knocked. There’s a crank in there named Darlington. I asked him some questions and he got sore. You know the rest.”

“What did he say?”

“He says he isn’t interested in murder — and doesn’t know anything about it.”

“Isn’t interested, eh!”

Sergeant Mathers stepped forward and pounded on the door. “Every tenant in this building is in for a questioning by the police.”

Agent “X” jerked his thumb toward the door of the Banton Detective Agency. “What about him, then?”

Mathers shook his head.

“We know all we need to know about Banton.”

Agent “X” relapsed into silence.

There was no sound in Darlington’s office at Sergeant Mathers’ knock. Not until the detective took out his automatic and began to hammer on the panels with the butt, did the door open again. Then Darlington’s face was contorted with fury.

“Can’t you leave a man alone?” he snarled. “Do you want me to call the police?”

“You’re talking to the police now,” said Mathers grimly. “You’re going to answer a few questions that will go down on the official records.”

“I’ll answer no more of anybody’s questions,” snapped Darlington.

“No?”

“No!”

Sergeant Mathers nodded and thrust out his jaw. “Just for that, Mr. Darlington, you’ll take a little trip down to headquarters and talk to the inspector himself. I’ve orders to round up all suspicious characters.”

Grasping his opportunity Agent “X” crowded back into Darlington’s office, his eyes veiledly alert. He identified the big instrument on the tripod supports as a spectroscope. That upheld Darlington’s claim that he was investigating light. But what about his complex, costly chemical equipment? It seemed to indicate that sunlight wasn’t his only line of research. Deftly, unobtrusively, Agent “X” began a cursory examination of the laboratory’s contents.

Here was a vacuum pump with a chamber for experiments in rarified air. There was an oxygen storage tank. There a high-pressure Bunsen burner. He lingered a moment over this, his eyes deeply speculative.

Darlington interrupted his meditation, stabbing an accusing finger in his direction.

“Take that young man along, too,” he said bitterly. “He’s an impertinent trespasser.”

Mathers snorted scornfully. “We got troubles enough without getting fussed over every snooping news hound in town. Get out of here, you! Scram!”

He shoved Agent “X” out of the laboratory, hustled Darlington into his hat and coat, and, with his colleague, drew the gaunt, protesting crank into the corridor. Then he locked up.

But as they pushed along the hallway Banton’s door opened. The fat detective stood in the threshold, his small, cunning eyes narrowed.

“What’s all the racket?” he asked,

“None of your business, Shamus,” snapped Mathers.

Darlington held back, jerking a thumb toward Banton, and raising his voice.

“He’s a neighbor of mine — a friend. He’ll tell you this is outrageous. He’ll vouch for my good character.”

“Somebody will have to vouch for his first,” said Mathers sneeringly. “Come on, Santa Claus — the inspector’s waiting.” He gave Darlington’s arm a vicious jerk.

Secret Agent “X” pretended to follow them, but stopped when he reached the head of the stairs. Banton had gone back into his office, and “X” retraced his steps quickly. Would this be a good time to talk to the detective again, or would it be better to wait and watch?

WITH a shrug the Agent turned and opened Banton’s door. Then he paused in brief surprise. The detective’s offices were more luxurious than he had anticipated. The green rug on the floor was soft as a grassy lawn. Crystal clear mirrors lined the walls. The woodwork was highly glossed. The furniture of the latest modern design. It might have been the sanctum of a millionaire broker. What was the basis of Banton’s evident prosperity, strangely at odds with his whining, seedy look? And was it pure coincidence that Banton was friendly with Darlington, who did secret research in a laboratory filled with chemicals?

Then he caught a glimpse of Banton through the open doorway of an inner office. The man was sitting back in a handsome swivel chair, hat tipped over his eyes, a cigar stuck between thick lips.

The agency detective seemed to be in deep and troubled thought, but he took his feet down, swung around, and glared as Secret Agent “X” entered.

“What the hell do you want? I thought I told you to run along.”

“X” assumed the tone of a disgruntled reporter.

“You didn’t give me a break. Now I got some more questions to ask you.”

“The cops wouldn’t tell you anything, eh — so you come back to me?”

“That’s right. I thought you looked like a good guy.”

“Well you can high-tail it back where you came from! Let the cops hand out their own dirt. I ain’t spillin’ anything tonight. I’m busy.”

Banton didn’t look busy, but there was malignant hostility in his shrewd, piglike eyes.

“That guy Darlington that the dicks just took down to headquarters says you’re a friend of his,” said the Agent. “I thought you could give me a little dope on him.”

Banton burst into raucous and jeering laughter. Then his face clouded.

“Friend, my eye! He’s just an old coot with some money and a lot of crazy ideas.”

“What sort of ideas?” asked “X” softly.

For a moment a look of fury blazed in Banton’s eyes. His face muscles twitched. He gripped the arms of his chair as though holding himself down.

“Find out for yourself, mug,” he rasped. “What the hell do you think I am — an information bureau? If you want to hire a detective, let’s see you come across with the fee — half down and half when the case is finished is my way. Now shut up and get out.”

Agent “X” drew a cigarette from his pocket. He lighted it, sat down on Banton’s desk, and flourished his notebook.

“It won’t hurt you to give me a little dope,” he said stubbornly.

Cords in Banton’s neck stood out. He rose suddenly, made a threatening movement toward Secret Agent “X.” Then he paused. His eyes turned toward the door, and Agent “X” turned, too.

The door of the outer office had opened and closed quickly. A girl stood just outside. She was a strikingly pretty girl with hair as black as jet, eyes like agate, and a smooth, olive complexion.

She moved forward on exaggeratedly high heels, swinging her lithe hips with the smooth, easy grace of a dancer. She was a girl who would have attracted attention anywhere. The paleness of her face seemed accentuated now by some deep, hidden emotion. There was emotion in her black eyes, too, making them snap and sparkle like fire seen through dark glass. Her hands were white and tense on the smart beaded bag she carried.

She looked from the agency detective to Secret Agent “X” and back again.

“I would like to see Mr. Banton,” she said, “alone.”

Agent “X” hesitated for only a moment. In that moment he was filled with wonder as to why the girl was here at all. And his gaze lingered an instant on her exotic, brooding face. Then Banton’s voice sounded harshly.

“Can’t you see I got a client? Didn’t you hear what she said? Scram!”

Agent “X” shrugged and rose. He jammed his notebook in his pocket, pulled his slouch hat down with a vicious tug, manifested all the mannerisms of a disgruntled reporter. With his cigarette dangling from his lips he went out the door and slammed it after him; then took pains to make a noise in the corridor as he walked away toward the stairs. But, as he looked back, he saw Banton’s shadow on the frosted glass and heard the click of metal. The agency detective had taken no chances. He had locked the door.

IT was then that Agent “X” paused and retraced his steps a second time. Banton and Banton’s client interested him strangely. How had the mysterious-looking dark-faced girl known that Banton was in his office so late at night? Who was she? Had she, too, been waiting outside and seen Banton enter? If so, what was her business with the ex-police lieutenant turned sleuth? Had it any connection with the hideous bank murders?

No one was in the corridor. Coming close on tiptoe to the door of Banton’s office, Agent “X” pressed his ear against the frosted glass. But he heard nothing, not even the low buzz of voices. The two inside had retired to the inner room.

Agent “X” might have picked the lock. But he didn’t want to be discovered prowling by Banton. If there was any reason to suspect Banton it would not do to arouse the detective’s own suspicions. There were other ways in which the Agent could work.

He took from his coat an article which looked at first glance like a small pocket Kodak. Opened up, the illusion was still maintained. But there were nearly twelve feet of what appeared to be the camera’s black cable release. On the end of this was a circular disc.

Agent “X” unwound the cable, opened the instrument’s back, and placed it to his ear. Then, standing on tiptoe, he thrust the end of the black cord up over the door through the ventilating transom. The instrument he held in his hand was not a camera, but an electric amplifying device, sensitive and delicate as a watch. He turned a rheostat control which corresponded to the film wind of a camera.

The voices of the man and woman now came to his ears as a confused buzz. They were talking evidently in the closed inner office. Through the thickness of a doorway and through many feet of air the vibrations of their voices came to him. But not even the ingenious amplifier in the Secret Agent’s hand could reduce their conversation to perfect clarity.

He listened tensely, ready to snatch the amplifier away if steps should sound along the corridor. His fingers moved the tiny control lever, reaching the most delicate adjustment possible, making the girl’s voice more distinct.

“—to help me,” she said. “I know what I’m talking about.”

The girl was silent. Banton’s voice came, confused, rumbling, making the diaphragm of the amplifier tremble so that words were blurred. Banton seemed to be arguing.

As Agent “X” worked with his control, the girl spoke again. The first part of her sentence was lost, but the last four words were arresting, making the Agent’s eyes brighten, glad that he had taken pains to come.

“—Davis was my friend.”

Davis — that was the name of one of the bankers who had been killed. Other words, caught here and there, verified this — words such as “murder,” “dead,” “robbery.”

The girl’s visit to Banton then had some direct connection with the raid tonight on the Merchants’ and Manufacturers’ Bank. Her agitation was an outgrowth of that terrible crime. Here was a steer that any detective would have followed. To Agent “X” it was a path that might lead to almost any unexpected thing. The girl hadn’t gone to the police. She had gone to Banton. This meant that she had something to hide. Agent “X” pondered tensely.

Darlington with his strange laboratory. Banton, combative, shrewd and suspiciously prosperous. This girl who had known Davis.

They formed a trio worth watching — and one of them might well lead him closer to that trail of hideous murder.

Chapter VIII

THE girl and man inside sank their voices to even lower pitches. Twice more “X” caught the name Davis. But the sentences were disconnected and confusing.

When talk ceased, when he heard the stir and scrape of chairs inside, he drew his microphone from the transom, coiled it up, and stepped back.

Quickly he moved to the angle of the corridor and waited there, crouching in a dark doorway, till the girl came out of Banton’s office and hurried to the stairs. He got one glimpse of her face. There were crimson spots of excitement in her olive cheeks. Her dark eyes were snapping like fire. He heard the click of her high heels as she moved down the stairs, and, like a shadow, he followed.

Banton he could locate any time. But who was the dark-eyed girl, and what was her interest in the dead banker, Davis? It was this that Agent “X” wished to find out.

When he reached the street floor, moving silently down the stairs, he saw the girl standing in the shadow of the building’s vestibule. He saw her look along the street in both directions before moving out, saw her slink into the shadows and walk like a person who does not want to be observed. He followed, taking care that she should not see him. Four blocks away, he saw her summon a cruising taxi.

The crowd around the bank, still tense, talking excitedly, was beginning to disperse. Cabs were hovering about, anxious to pick up a few late fares. Even death had its profits. Agent “X” signaled one of the circling taxis.

“Follow the cab ahead,” he said. “Keep it in sight.”

The driver cast a frightened look at his fare, then nodded. There was nothing sinister about “X” in his present role. His appearance was that of an intent young newspaperman.

The cab lurched away along the dark street. It was after twelve. Much had happened in the past two hours. The period had been a veritable cyclone of danger, death, and mystery. And the excitement was not over. The pieces of the ghastly murder puzzle lay scattered on the face of the darkness. Agent “X” was trying to gather them up.

The cab bearing the strange black-eyed girl turned into an uptown avenue. It sped quickly, as though its passenger were impatient. In ten minutes it turned east, followed a cross-town street, and entered upon the plaza of a big interborough bridge.

Its red tail-light winked up the long slope of the bridge, reached the summit and went down the other side. It left the bridge and entered a wide thoroughfare. They were in a different borough now. The chase had led away from the scene of murder. But Agent “X” had learned that the ramifications of murder lead far.

For a half-hour more the chase continued. Agent “X” was getting uneasy. What if the girl in the cab ahead got on to the fact that she was being followed? He wished he were driving one of his own cars. There would have been less chance of his being seen.

They came to the suburbs, at last, followed a long concourse. The Agent breathed easier. There were many cars here despite the lateness of the hour. Romantic couples out for a night drive. Theatergoers returning from shows in town.

He ordered the cab to creep closer.

Then the taxi ahead swung off the boulevard, plunged down a smoothly paved side street between wooden suburban houses. “X” knew where he was now. A sudden premonition came. He sat forward tensely in his seat.

Against the night sky, the great beam of a searchlight swept back and forth with rhythmic monotony. It was like a huge waving arm. It was an airbeacon. Ahead of them lay the newly equipped municipal flying field, the field where night mail planes landed and took off, where there was always alertness and a bustle of activity. The great hangars housed many small planes. Agent “X” had visited the field often, flown from it himself.

Was the girl going there now?

There could be no doubt about it. Her taxi turned into the wire enclosure, headed into the parking space, with the black bulk of the hangars beyond. Landing lights were on. The deep-throated roar of an airplane motor sounded.

Rutted mud made the Agent’s taxi jounce like a ship in a stormy sea. “X” ordered the driver to stop. He glanced at the meter, leaped out. It had run into several dollars, but he paid the driver twice the amount. Then in the semigloom surrounding the big, lighted field, he strode after the other cab with the girl in it. It had stopped, too. The girl was getting out.

The swinging, persistent arm of the air beacon lighted Agent “X’s” face. The bright, excited glow in his eyes wasn’t entirely the reflection of the searchlight’s radiance. The cab which had brought the girl moved off, swung around, bumped by in the darkness. It was headed back toward the city. The girl strode on.

“X” got a silhouetted glimpse of her figure. It seemed to express determination, hurry. He saw her go into the field’s operations office and speak to the man at the desk. Night planes were coming in and leaving on regular schedule. But the field’s sightseeing, joy-riding ships were shut in their hangars, housed for the night.

THE man in the operations office shook his head as Agent “X” watched through the window. Then “X” saw the girl display a roll of bills. He saw her toss them down on the desk. The man in the operations office smiled and finally nodded. He motioned the girl to a seat, picked up a telephone. The girl sat smoking, holding a cigarette between her long, carmine-tipped fingers. Her slimly shod foot tapped impatiently. There was worry in the dark, heavily lashed eyes.

A half-hour went by and a pilot came into the office. He looked sleepy, sullen. There was a helmet with goggles on it hanging carelessly over his arm. His sleepy eyes brightened as he saw the waiting girl. The droop left his shoulders. He had been waked from sound sleep, apparently, to take a passenger up. Now he showed interest.

Agent “X” stiffened. There was no doubt as to what the girl was going to do. She had hired a plane and was going up. Why?

Only the dark night, sky or the girl herself could answer that question. But he didn’t wait to ask it.

He turned, looked out across the wide field. A mail plane was on a dolly, being wheeled out and loaded. Mechanics were swarming around its engine. His eyes went beyond it.

A private hangar was open. Lights showed inside. Two planes were out on the dead line, one was warming up. It was a small, two-seated ship, a sport plane belonging to some rich playboy. No doubt he was going to take his girl for a night ride.

Agent “X” struck out at a run toward it. Employees of the flying company were wheeling another plane from a hangar, one of the regular company ships. Orders had gone out from the operations office. A mechanic turned the handle of the inertia starter. The motor coughed, sputtered, broke into a roar.

It was almost warm by the time Agent “X” reached the vicinity of the smaller plane. The pilot was helping the girl in. She had on a helmet and goggles provided by the company.

Agent “X” looked toward the open door of the hangar before which the smaller plane squatted. He saw figures inside; the playboy who owned the plane was adjusting his helmet.

The motor of the small plane was humming sweetly now. And behind “X,” down the field, the company ship leaped away to taxi into the wind.

Like a swift, silent wraith, Agent “X” darted from the shadows. He reached the small sport plane, drew the chocks from under its fat air wheels. In a moment he had vaulted into its cockpit.

He looked behind. The owner of the ship hadn’t even left the hangar.

As the company ship pivoted far down the field, nosed into the wind, and rushed forward with a song of power, Agent “X” pushed the throttle of the sport plane home.

He raised the tail off the ground, raced forward with a steady hand on the stick. The amazed shouts of the plane’s owner in the hangar behind were drowned in the engine’s blasting crescendo. The lights of the hangar rocketed away. The lights of the other ship were passing overhead.

Agent “X” taxied forward, kicked left rudder, turned.

The sting of the night wind lashed his unhelmeted head. He crouched behind the low wind cowling, fed gas to the motor. A moment more and he had drawn the stick back, drawn the plane off the ground, and was roaring up into the black night sky.

Chapter IX

THE eyes of Agent “X,” sharp as a hunting hawk’s, spotted the exhaust glow of the other ship. He began to climb. The small sport plane, built for speed and aerobatics, had the swift grace of an arrow. A connoisseur of fine planes as he was of cars, Agent “X” knew that Fate had been good to him tonight. The high-speed radial motor in front was pulling the ship up like a rocket. Already he was on a level with the sky craft ahead.

He climbed higher still, getting above it, keeping that tiny, flickering exhaust plume in sight. Where was the other ship going? What strange objective did the mystery girl have that she needed to take this midnight flight?

The two-place ship ahead didn’t even circle the field. It climbed steadily into the wind, then turned at right angles in a steep bank and bore away toward the city. This surprised Agent “X.” He didn’t know what he had expected, but it had seemed likely that the girl would fly away from town. Instead she was flying toward the heart of it.

The miles that had taken nearly an hour to traverse by land were flown in a few minutes on the wings of the wind. The altimeter of the Agent’s ship showed two thousand feet. He was mounting still. Far below, he saw the smooth ribbon of the boulevard with lights strung along it like bright pearls. The speeding cars were crawling beetles.

Wispish, low-flying clouds swept across the sky. The Agent took advantage of them, nosing up out of sight from time to time, dropping again to keep the other ship in view. It flew steadily toward the city, until the thin silver band of the river was beneath them. He saw the bridge they had crossed, with the crawling lights of motors and trolleys on it.

Then he caught his breath. The other plane, climbing now, was headed straight toward that section of town where the Merchants’ and Manufacturers’ Bank was located. Against the sky line for a moment, against the farther river which made an island of the city, he saw the flat-topped, eighteen-story skyscraper that housed the bank.

Then he drew back on his stick to keep above the other plane. Once again he rocketed up into the low-flying clouds. He swept through them, climbed on into the clear, cold starlight.

He let another thousand feet register on the altimeter, waited, and saw the hired plane burst through the layer of clouds like a monster breaking the surface of some white sea. For a moment he nosed down, shutting off his motor. He heard the engine of the plane beneath pop once, and saw the ship nose down, its motor silent, too. It swept back toward the clouds in a long, descending bank.

Agent “X” pushed the stick forward and dived. With his propeller still ticking over, but the engine silent, he shot down toward the clouds with the wind whistling a chant through the struts and flying wires. The clouds rushed up to meet him. He saw the other plane disappear.

Alert, tense-faced, he followed it. The whip of the mist around his head was like a cold plunge. Then he broke through. The other plane was below and ahead. It had flattened out now. In a long, silent glide it was headed toward the bank building.

Like a winged wraith Agent “X” followed. There was small chance that they would see him against the clouds. Little starlight came through. The lighted streets against which he could glimpse the plane below formed a better background.

But what did this strange maneuver signify? In his anxiety to find out, he steepened his glide, picked up speed, and swept closer to the ship ahead. Did the girl plan to drop something on the bank?

But no. As the plane below swept over the bank he was not more than five hundred feet behind. For a moment, against a street beyond, he could see the helmeted head of the girl scanning the top of the bank. But she dropped nothing, made no movement. The plane continued, banked away, nosed down till it had picked up speed again. Suddenly the roar of its motor sounded. It shot up toward the clouds.

Agent “X” waited, then switched his own motor on. In the dull drone of the ship above, the sound of his own engine would be lost. He passed over the bank, looked down. All was black on the flat-topped roof. The big building seemed peaceful. There was no hint of the appalling thing that had happened in it tonight. He wondered if Banton were still in his office — and if he knew that his client was sailing the night skies far above him.

The two-place ship disappeared into the clouds. The Agent’s sport plane was answering its propeller, rocketing up in a magnificent burst of speed.

Back in the clouds again, he kicked right rudder, bore away. When he burst through them he was flying at a different angle from the other plane. He swung around in a wide circle and followed, climbing above it once more. Afraid that he would be seen, he continued to climb till his altimeter registered eight thousand feet, until the air was still and cold and so thin that his ears began to ring, until the plane below was a mere speck on the white surface of the clouds. Then again he shut off power and nosed down over it.

IT was headed away from the city, but not back toward the flying field. The mysterious girl passenger had not finished her night flight yet.

Through holes in the clouds Agent “X” could see the glint of water now, and the lights of ships. They had nosed out over the harbor. The clouds became more ragged. The other ship was harder to see. He nosed lower.

The ship with the girl in it was following the shore line of the harbor now. It began to circle, and, diving low with motor shut off, Agent “X” saw the girl leaning over the side, peering down. The plane went down through the clouds. Agent “X” followed.

He hung just under the clouds while the other ship continued dropping. He could follow its exhaust flare once more. Then he saw lights strung along the shore in a curve — the lights of a harbor. He strained his eyes to see through the darkness. The water below cast wavering reflections. The night seemed filled with mystery. What was the other plane doing?

It continued to circle, going three times around the harbor as though the girl were looking for something, or familiarizing herself with the location of this place.

Agent “X” made out gray shapes on the water now. Boats. But the ship ahead was not a seaplane. It couldn’t land. Again he watched for some signal, saw none. The clouds drifted more thickly. He could see only the feathering exhaust of the plane below.

The plane left the harbor at last, started back along the shore again toward the city. Then Agent “X” caught his breath. He was gliding with motor at idling speed. It seemed to him suddenly that he detected another sound. The air seemed to be filled with a throbbing note. He looked up, started.

For an instant he saw a firefly spark against the black under surface of the clouds.

The spark winked, disappeared, came on again. He closed his own motor entirely, glided down toward the water a thousand feet below. Then the hair on his neck began to rise.

Far above him he heard the thin, high wailing of wind shrieking through speeding wires. A ship was coming down from the clouds in a fast dive.

HE looked ahead toward the two-place company plane. The feather of its exhaust was still visible. Then, as though the curtain of the night had opened up, the long, lavender beam of a searchlight stabbed down from the clouds. It leaped across space like a lightning bolt, focused on the plane with the girl in it.

In that first glance Agent “X” could see the white goggled faces of the girl and the pilot staring up. The beam of the searchlight narrowed. The other plane was sweeping close. What did it mean?

In an instant the answer came.

A series of stuttering, rhythmic reports sounded in the sky above. Agent “X” saw a winking, vicious pin point of light close to the spot where the searchlight came from.

The mysterious plane that had dived out of the clouds was shooting, firing mercilessly at the girl and the pilot ahead.

He saw the pilot bank to the left, sideslip away. An instant the searchlight lost it, then picked it up again. Like a terrible, all-seeing eye the lavender beam held its mark. The pilot ahead had apparently had no wartime training. He knew nothing of defensive air tactics. It made sweat crawl along Agent “X’s” spine. This was butchery, slaughter, murder he was witnessing.

He fed gas to his own ship, raced forward. But there was nearly a thousand feet of intervening space. The horrible rat-tat of the machine gun on the plane above sounded again. The finger of the searchlight was focused on its mark.

Then, as Agent “X” came nearer, he saw, under the searchlight’s glare, like a horrible tableau, that the pilot had been hit. The man was jerking in the cockpit. The plane gave a crazy lunge forward, sheered off on one wing. The merciless death beats of the machine gun continued.

The pilot ahead flung out one arm, turned up an agonized face. Then he gripped the stick, pushed it forward, dived toward the water.

Agent “X” knew it was the worst thing he could have done. Wartime pilots were trained never to fly away in a straight line. “X” remembered brilliant wing-overs, rolls and Immelmann’s he had seen — the strategic air maneuvers of skilled aces who could throw an enemy off. Even for him it would have been a simple matter to avoid that groping searchlight’s beam.

But the pilot ahead was helpless, wounded, and ignorant of combat tactics.

At last the plane sideslipped, did a falling leaf maneuver, then nosed into the surface of the water with a burst of billowing spray.

Chapter X

FOR one horrified instant Agent “X” watched. The searchlight still played over the crashed ship. The air spaces in the wings were holding it up — holding it till bullet holes filled and the plane sank from sight. The figure of the girl was visible. As the spray subsided he saw her struggling desperately in the rear cockpit.

The searchlight shifted. The murder plane nosed up from its dive, and Agent “X,” eyes bright and bleak as steel, thrust his control stick forward.

There was no hesitancy in his movements now. There was only one thing he could do. In a matter of minutes, seconds perhaps, the heavy engine of the crashed plane would pull it beneath the surface, dragging the girl with it.

Wind howling through struts and wires, Agent “X” roared down. He had no searchlight to guide him. But horror had marked the spot where the other plane rested. Faintly against the gray surface of the water he could see the distorted floating mass. He put on a burst of power, plummeted in a dive that made the wings shudder. At the last he flattened out, pulled the nose of the ship up and pancaked into the cold swells. On the chance of saving a human life he was deliberately wrecking a four-thousand-dollar plane.

The fat air wheels struck first, ploughed through the water. The landing carriage groaned as though in resentment of this harsh treatment. The engine’s hot cylinders took water with a boiling, bubbling hiss. And Agent “X,” cleared of his safety belt, leaped the instant the plane began to settle. He had unlaced his shoes, kicked them off. He struck out toward the spot where the other plane had landed. The water was cold, freezingly chill against his body. And his movement in it was a strange transition from the swift sky progress he had been making.

He took a half-dozen quick strokes and listened. Something slapped against the top of a wave. The wing of the fallen plane. He heard a faint, shrill cry that sent the blood racing through his veins.

He didn’t try to explain to himself the reasons behind the thing he had seen. There would be time for that later. His one thought now was to save a human life. There had been enough of murder already.

Something rose out of the water ahead of him. It was a wing of the plane, canted. That meant that the other one was broken — or else the ship was already beginning to sink. The cry came again. There was a note of horror, fear, in it that wrenched his heart.

He gripped the wing, pulled himself along it hand over hand, racing his body through the water. He passed a strut top, two, neared the fuselage of the plane. Then dimly he saw the girl ahead. She had gotten out of her safety belt. She was clinging to the coaming of the cockpit. He couldn’t see her face, but he called to her.

A smothered intake of breath answered him. There was a moment of silence. Then her voice sounded, scornful, fierce as a trapped animal’s cry. “Murderer! Butcher!” There was in her speech, too, the faint trace of some foreign accent.

Her words were like a blow. Agent “X,” treading water, gathered his thoughts. Who did she think he was? What did the girl mean?

“I heard your plane crash,” she said bitterly. “I hoped you’d been killed. Now I suppose you intend to finish your work!”

The Agent spoke softly. “I’m not the person you think. You’ve made a mistake.”

“Who are you then? You’ve killed my pilot. He’s dead — dead, I tell you — and you are going to kill me!”

“It wasn’t I who shot at you,” he said. “I saw you crash and came to help.”

A harsh, scornful laugh came out of the darkness. “You expect me to believe that — butcher!”

There was another moment of tense silence, then Agent “X” spoke again.

“Listen!” he said.

He could almost feel the girl in the darkness straining. Then she cried out.

“It’s someone coming to rescue me. You can’t kill me now!”

She gave a sudden, piercing scream, a cry for help, waving her arm and beating against the canvas cockpit of the plane. Agent “X” reached forward and caught hold of her. She screamed again and tried to wrench loose.

“Be quiet!” he hissed. “They aren’t coming to help us. They are coming—”

He didn’t finish the sentence. The roar of a plane’s motor was louder now. Once again the bright, questing beam of a searchlight flicked on. It swept across the water, centered on the wrecked plane.

AT almost the same instant the Agent’s ears caught the horrible, rhythmic tattoo of a machine gun again. Bullets slapped into the water in a burst not fifty feet away.

In the glaring glow of the searchlight’s beam he saw the girl’s white, terrified face. He looked beyond her, got one ghastly glimpse of the dead pilot slumped over his controls, his body riddled with bullets.

For one tense instant the girl turned toward him.

“I was wrong,” she said. “I’m sorry — they are going to kill us.”

“Not if we can help it,” he grated. “Quick! The plane’s sinking!”

She gave a moan of stark terror then. “I can’t swim,” she said.

It was as though all the hideous fiends of hell were chuckling, conspiring to create a nightmare there in the darkness. They were almost a mile from shore! The girl couldn’t swim! And now armed killers above their heads, relentless, purposeful were trying to slay them as the pilot had been slain. Agent “X” spoke quickly, harshly.

“Put your arms over my shoulders — so. Hang on — but don’t throttle me.”

Trembling, the girl obeyed. For a moment he felt the softness of her body against him, then they were free of the plane. But before he had taken two strokes, the searchlight had swept close.

It seemed like some terrible, monstrous eye, leering at them. The thunder of the plane’s motor was a deafening cascade of sound in their ears. It even drowned out the measured beat of the machine gun.

But bullets snapped and crackled into the wreckage just behind them. Bullets beat around them in the water. The girl screamed again, shrilly, close to his ear, and he thought for a moment she had been struck.

Another salvo of shots fanned the water just ahead. He felt his lips moving, felt himself cursing at the murderous fiends overhead. The plane swept on, so close that he could feel the wind of its propeller. He turned his head, saw to his horror as the plane was outlined for a moment against the glow of its own searchlight in front, that it had pontoons. It was a small, swift seaplane.

The searchlight clicked off, the plane was banking now, getting ready to land and make sure that its terrible work was done.

With all the strength in his body Secret Agent “X” forged ahead through the water, carrying the girl on his back. The steady clutch of her fingers showed that she was unharmed. But he knew that their danger wasn’t over. There was the threat of death by drowning ahead, the threat still that the murderer in the seaplane would find them and riddle them with bullets.

For that reason he almost burst his lungs to put as much distance between them and the wreckage as he could.

He heard the other plane come to rest on the water, heard the pontoons squash, and the motor cut to idling speed. The plane was taxiing over the surface now. The searchlight stabbed on again, swung around toward the wreckage, focused on it. Then the plane came forward.

Hardly daring to breath, Agent “X” swam on. He didn’t go straight toward shore. Instead, he moved off at an angle. In a second he was glad he had done so. The searchlight on the plane began to swing around. It swept across the water, straight toward the shore. For a moment he pulled the girl beside him and held her there with only her face out.

A reflected glow from the searchlight was playing over them. He feared the terrible lash of bullets, feared death not for his own sake, but because he had a life to save and work to do. He could feel the wild pounding of the girl’s heart close to him.

THE searchlight shifted, turning back on the wreckage again. For seconds the unseen killer in the plane examined his handiwork. He still seemed unsatisfied. A red flare came from the plane’s exhaust stack. It streaked across the water, taxiing again.

It circled in a wide arc, came back. This time its searchlight bobbed over the water so closely that Agent “X” gave up hope and waited. But the slow-rising swells served as a precarious, protecting barrier.

The plane taxied by, with the two of them just outside its searchlight’s path.

Agent “X” swam on. The plane circled again. It had become a wild, desperate game of hide and seek out on the blackness of the water. The pilot, hideous criminal that he was, wanted apparently to make sure that no one survived. Some tremendous issue appeared to be at stake.

Seconds passed and “X” saw another light far off on the horizon. Another plane seemed to be coming, perhaps from some coast guard station or army field, or perhaps the owner of the ship he had borrowed.

That ship would have to be replaced now. Betty Dale with her newspaper connections would find out the owner’s name for him, and he would see that an amount large enough to cover the loss of the ship was sent to the man anonymously. To save a human life, to come closer perhaps to the solution of this ghastly murder mystery, beside this the loss of a plane was nothing.

He saw the murder ship leave at last, frightened perhaps by the approaching light. But the light on the horizon passed far overhead. “X” concluded it was a coastwise mail plane on one of the big transport lines.

The long swim to shore began. Agent “X” didn’t try to hurry. He was too experienced a swimmer for that. Minute after minute he made his long, clean strokes tell. The girl seemed to be beyond speech. She was clinging to him as if frozen. When at last he heard the sound of waves breaking on the beach, he thought perhaps she was chilled to the point of death.

His feet touched sand. He reeled through low surf to the shore, staggered up a beach. Then for a moment he laid the girl down. She sagged limply. He felt her face, rubbed her hands.

“Your name?” he said. “What’s your name? Where do you live?”

She groaned, stirred. He repeated his query, again and again, shouting it in her ear. As though it had reached her from a long way off she answered at last, mechanically, feebly.

“Rosa Carpita,” she said. “Rawleigh Apartments.”

She muttered something else, something that “X” couldn’t understand. She sank back limply into the unconsciousness from which his shouted questions had half aroused her.

HE looked tensely about. There was a bluff at the top of the beach. He saw it silhouetted against a glow in the sky. The glow seemed like lights. He picked the girl up bodily, cradled her in his arms, and strained forward up the sand. He labored up the bluff.

There were lights beyond — a cross roads with a spray of three electric bulbs strung on a pole. Far down one of the roads two spots of radiance were approaching. He ran with the girl in his arms across a rough field. Holding the girl beside him, he waited and signaled the car whose lights he had seen.

It was a farmer’s truck, coming into the city with crates for early morning shipment. The man on the driver’s seat stared at “X” skeptically, then saw the girl.

“We capsized in the water,” said Agent “X.” “This girl has fainted. I’ve got to get her back to the city.”

The farmer nodded. “Get in,” he said.

For many minutes they bumped and jounced over the dark night road, coming at last to the outskirts of the city. Agent “X” saw a taxi. He thanked the farmer and transferred his burden to the swifter vehicle.

The driver didn’t know the address, but a directory in a drug store telephone booth gave it.

In twenty minutes the cab drew up before a large apartment house. It was a luxurious place, with a canopy over the sidewalk and a gilded foyer. The doorman had long since gone off duty, but the night switchboard operator let Agent “X” and his limp burden in. Rosa Carpita was breathing regularly. She was in a state of exhaustion from the fright she had had and her long submergence in the water.

The switchboard girl summoned a janitor who showed the Agent to Miss Carpita’s apartment. “X” turned to the man, spoke quickly.

“Get a doctor,” he said. “This young woman almost drowned. She needs care at once.”

The janitor hurried off. Agent “X” deposited the black-eyed girl on a couch and made her as comfortable as he could. She was unwounded, unhurt. He had saved her life. But she might be unconscious for hours, and, if she came to, she would be in no condition to talk. He doubted if she would anyway. Whatever her mission into the night skies had been, it was veiled in mystery. He would send Betty Dale to question her in the capacity of a Herald reporter, and later he would come to see her again himself.

He looked around her apartment a moment. There were many pictures of stage celebrities on the walls, some of them autographed. There were some of the girl herself in costume. He found a sheaf of press notices stacked under a paper weight. He scanned them quickly.

The girl was Rosa Carpita, Spanish dancer, who had appeared in many revues and night club skits. The luxury of her apartment attested to the fact that she was successful.

Then Agent “X” gave a start and stepped forward. On a table at the end of a room a large photograph was set between two upright lights. It was the photograph of a man, a face familiar to Agent “X” who never forgot any face that he had once seen actually or in the press.

It was the face of Jerome Davis, one of the three murdered bankers, and on it was an intimate line: “To my dear Rosa from Jerry.”

Chapter XI

WITHOUT waiting to see more, Agent “X” left the Rawleigh apartment. A doctor would soon be there to take care of the girl. There would be inquiries, perhaps a police investigation. The Agent was wet, uncomfortable. He took a taxi to the nearest of his hideouts.

There he changed his clothes and lay down on a couch for a few hours sleep — an unusual thing for him.

But the close call with death under the merciless flame of the Flammenwerfer, the wild ride in the night skies, and the long swim through icy water had left him utterly exhausted.

When morning dawned, newsboys in the street began crying scare-head editions. Black headlines were spread across the front pages telling of the ghastly bank murders, and the disappearance of two bank employees. There had been another robbery and murder, too, another charred corpse left behind. A jewelry store in an outlying part of the city had been robbed and a cop who had gone to the scene too soon had been killed. The city was in the grip of an appalling crime wave.

Agent “X” visited the scene of this robbery also, saw the safe which had been blasted open by some cracksman who knew his job.

Why, he wondered, hadn’t the same men, raiding the Merchants’ and Manufacturers’ Bank, used a nitro charge, too? If they made a second raid they probably would. He hoped the special guard would be adequate.

There were many other things in the paper to interest Agent “X.” There was the story of a passenger plane leaving the municipal field and not returning, and of another plane being stolen.

Both were insoluble mysteries.

A young woman, Martha Rollins, dark-eyed and exotic, the paper said, had hired the plane the night before under strange circumstances. Pilot Steve Howden of the field’s flying service had flown her. It was feared that they had cracked up somewhere.

The girl then, Rosa Carpita, had used an assumed name on the company’s books. Agent “X” read the other story, the tale of the stolen ship. The paper could ascribe no motive for the theft of that unless some bandit was making a get-away. The plane had belonged to a millionaire’s son named Kirkland.

Interesting also to Secret Agent “X” were the details of the three bankers who had been slain, especially the short life history of Jerome Davis. Davis was married, the paper said. His wife was abroad. From what “X” gathered, their marriage was a social affair with little love between them. He thought again, then, of the dark-eyed girl, Rosa Carpita.

Calling Betty Dale on the phone he asked her if, in her capacity as Herald reporter, she would go to the Rawleigh Apartments and make a few inquiries. Betty did so, but her report was disappointing. Rosa Carpita had left her home early that morning. The doctor had been in attendance upon her. It was believed she had perhaps gone away to the country as she had taken a grip with her.

He called next on the families of Spencer and Cox, the vanished bank employees. The police had been unable to locate these men. For hours their families had been besieged by detectives and newspaper reporters. Spencer had a wife and six children. His absence was a tragic mystery. But Agent “X” had heard of other bank employees, married and apparently honest, who had embezzled funds and left.

Cox had only a brother living. He was the operator of a garage. From him “X” gathered that the other bank employee had been a rather fast-living fellow, a bachelor who liked his good times. The papers, he noticed, played this up. It was even whispered that Cox was fond of the races.

In connection with this, and in the guise of an enquiring reporter, Agent “X” called on the two surviving bankers, von Blund and Marsh. Grave-faced and strained-looking, they were in their offices in the bank.

“You will understand,” said von Blund, “that after such an experience as we have been through we cannot give you much time. You are the twentieth reporter who has already—”

Agent “X” nodded and waved the protest down. He stared into the clean-cut, smooth-shaven face of von Blund. The piercing blue eyes, aristocratic features, and blond hair showed the banker’s Germanic stock.

“Tell me,” said Agent “X.” “It is a highly personal question. You may not care to answer it. But it is being hinted in newspaper circles that there were things in one or more of your deceased partners’ lives that their families would wish to cover up.”

For a moment von Blund started. “What do you mean?”

“Women, for instance. Unconventionalities.”

“You’re talking rot. My partners have unblemished records in every way.”

“There are reports that Mr. Davis was seen—”

Von Blund struck the desk sharply. “It is true that Mrs. Davis is in Europe. It is true that they spend a great deal of time apart. But that is neither here nor there. To my knowledge Jerome Davis was a man of impeccable morals and highest honor.”

Agent “X” nodded. He thanked the banker and left. Von Blund’s manner indicated that he knew nothing of any intimacy between Davis and the dancer, Rosa Carpita. But, since Davis had been married, and since his profession was such that he couldn’t risk any breath of scandal, it was quite natural that the affair should be kept under cover.

There were other lines of inquiry Agent “X” wanted to follow. He visited the family of the slain bank guard and questioned many people employed in the vicinity of the bank.

Then Secret Agent “X” did a strange thing. Retiring to one of his hideouts he disguised himself as a prosperous, middle-aged business man — a ruddy-faced individual with gray hair, eye-glasses, and lumpy features. He dressed himself in a suit of clothes to match the type and got from a near-by garage one of several cars he kept.

In a smart, expensive coupé, he drove directly to the building which housed the Merchants’ and Manufacturers’ Bank.

Business was going on as usual The bank’s doors were open. An armored truck stood close to the curb. A load of cash was being taken in, while grim-faced guards watched alertly from a distance. Depositors and business men were displaying their faith in this bank which had withstood the bandits’ raid.

Agent “X” went to the renting manager of the building. He presented himself as Andrew Balfour of the Midland-Central Utilities Company and, under this guise, rented an office on the fourth floor — one he had previously noticed was vacant.

IN the next hour, posing as Andrew Balfour, he acted the part of a slave driver. Like a man accustomed to getting things done at high pressure, he ordered immediate deliveries of typewriters, desk equipment, and office stationery.

He had a letterer put the name “Midland-Central Utilities Company” on the frosted glass of the door. He had his own office marked: “Andrew Balfour, Private.”

Then he visited an employment agency and hired several girl office workers.

As a business man of apparently substantial resources, Secret Agent “X” wandered again into Banton’s office, just across the corridor.

The private detective’s manner showed that he had already checked up on the building’s new tenant. He was suave and deferential with the oiliness of a man who hopes to get a new client.

Puffing a cigar, hands in vest pockets, Secret Agent “X” leaned back in the padded chair that Banton courteously provided him.

“There is a chance,” he said, “that I may need some investigating of an intimate nature done for me. I would like an idea of your fees and facilities.”

Banton was more than willing to oblige. While Agent “X” watched, listening and sizing the man up, Banton talked.

“My regular policy,” he said, “is one half down and one half when the case is finished. But for a man of your standing I’ll be willing to undertake any investigation with no thought of remuneration until the affair is finished. I have many competent assistants.”

Agent “X” got a glimpse of these — shifty-eyed men of the stool-pigeon type, men who could be trusted to climb in porch windows and steal evidence if it could not be obtained in any other way.

He thanked Banton and left, with the detective’s card in his pocket.

Darlington didn’t show up that day. Inquiries revealed that he had been released from headquarters. But Agent “X,” in the role of Balfour, stayed on in his office after his girls had left. To spy on Banton and Darlington without arousing suspicion had been his purpose in renting the place. Through Banton he expected to check up on Rosa Carpita, also. His engaging of an office force had been an elaborate blind.

In his shirt sleeves, surrounded with papers and files, he appeared to be furiously busy. Banton wandered in once to exchange pleasantries with the new tenant who gave promise of becoming a client. At intervals Agent “X” went to the mail chute in the corridor and kept his eye on both men’s offices.

It was toward nine that he saw again the flickering blue light in Darlington’s transom. The crank had returned.

Agent “X” ran up and knocked at Darlington’s door. When the elderly crank thrust his head out Secret Agent “X” bent forward excitedly.

“I beg your pardon,” he said. “I saw an odd light. I thought perhaps there was a short circuit — danger of fire, you know.”

“Who are you?” rasped Darlington.

“A new tenant — a neighbor of yours on this floor. I moved in today. Sorry if I disturbed you.”

Darlington was clad again in his stained smock. He seemed as busily absorbed as he had the night previous.

“You’ll learn to mind your business,” he snapped. “Good night, sir.”

With that he slammed the door in the Agent’s face.

For nearly an hour the wavering light in Darlington’s office continued while the crank pursued his nocturnal labors. Then, as Agent “X” made a trip to the mail chute, he saw that Darlington’s transom was black. The crank had apparently left.

All the offices on the floor except Banton’s were empty. The corridor was still.

Agent “X” walked quickly to Darlington’s door and knocked. There was no answer. He paused a moment, listened, then took a cleverly shaped pass-key from his pocket. With a twist of his wrist he opened the door and entered.

A window was raised, but the office was deserted.

Swiftly Agent “X” searched the place with his flash light. The probing beam covered every part of the room. It fell on the rows of books, the scientific instruments, the retorts and jars of chemicals.

Over these the Agent lingered longest, a questing glint in his eyes. The terrible Flammenwerfer gun was a chemical weapon. Was there sinister significance in the hidden researches of Darlington?

In a worn notebook Agent “X” discovered figures that Darlington had jotted down. They seemed to pertain to the velocity of light. Apparently the man was what he claimed to be. And apparently he had completed his investigations for the night.

Then Agent “X” saw an open leather case belonging to some sort of instrument — a camera it seemed, but one equipped for special purposes. There were holders for lenses and ray filters, metal frames for film packs. Where was the camera itself? Had Darlington taken it with him?

“X” left the office, went back to his own. When he came out again, Banton’s office, too, was dark. Agent “X” took a chance and slipped into it, but the papers in the detective agency gave no clew as to the man’s connection with Rosa Carpita.

Agent “X,” still in the role of Balfour, left and descended to the street. There were a half-dozen lines of investigation open to him — one to learn the whereabouts of Miss Carpita. He didn’t doubt his ability to do so. He anticipated a night of feverish activity.

Then suddenly he held his breath, pressed back against the side of the bank building. The blood in his veins seemed to run cold. From the darkness above him came a bloodcurdling human cry. It was a cry of fury and stark fear. The Secret Agent looked up.

He could see nothing, but echoes of that hideous cry whispered along the face of the building.

Then something that seemed like a giant bat with outspread wings hurtled down out of the darkness. It was ghastly, uncanny. The Agent stepped back, and as he did so something slapped the pavement at almost the precise spot where he had stood. It was the body of a man — the body of A. J. Darlington.

Chapter XII

WITH a sense of crawling horror Agent “X” stared. The awful smack of Darlington against the pavement told a story of its own. Every bone in the man’s body was broken. He lay face downward, a sprawled and hideous blob, arms and legs spread out. After that terrible cry, after the sight of him falling, the sudden silence that ensued was like a ghastly vacuum of death.

Then the vacuum was punctuated by the sound of thudding footsteps. One of the special guards stationed in front of the bank came running around the corner.

Secret Agent “X,” in the role of Balfour, pointed. He heard the guard’s horrified exclamation. The man’s face was a sickly white. Gingerly he bent over the prostrate form of the crank experimenter. Agent “X” was marshaling his thoughts. This was a development that in his wildest dreams he hadn’t anticipated. But even in that moment of surprise and horror he didn’t forget that he was playing a role.

“It’s Darlington,” he said. “The old gentleman who has an office on the same floor as mine.”

The special guard nodded.

“You’d hardly know him. He must have fallen or committed suicide. His office is right above here.”

It was true. Agent “X” looked up. The windows of Darlington’s room where he worked so late were directly above the spot on the sidewalk where the man had met such a ghastly end.

The guard stood erect, mopping cold sweat from his face.

“I heard him cry — I won’t forget it. This place gives me the creeps. Four guys murdered the other day — and now this bird tumbles out of his window.”

Agent “X” stood frowning, his eyes fierce and bright. He had been in Darlington’s office five minutes ago. He couldn’t tell the guard that. But Darlington hadn’t been there then. Yet here he was, dead, a blob of shattered flesh beneath his own window. It was mystery added to mystery.

The guard drew a whistle from his pocket, blew it. A police detective stationed outside the bank came to the spot also. Agent “X” had seen him before. Curry was his name.

“It’s enough to drive a man nuts,” said the special bank guard. “The old bird on the fourth floor has bumped himself off.”

Curry stood staring down, then began questioning the man he thought was Balfour.

Agent “X” answered mechanically. He was staring at Darlington’s body. The crank’s desperate cry and the sickening sound of flesh striking stone still echoed in his ears. It troubled Agent “X.” Even more than the actual horror of it was a question that repeated itself again and again. Where had Darlington been when Agent “X” was in his office? How had he gotten back so soon?

“Stay here,” said Curry to the bank guard. “I’ll go up and take a look at his place. Maybe he left a suicide note. He was a nut anyway. They had him down at headquarters last night. I guess the sweating they gave him was too much for his nerves.”

The detective strode off. Agent “X’s” first impulse was to follow. Then something detained him. He stared at Darlington’s body again, stared up at the face of the building. His eye traveled along floor after floor, lingered on the fourth, continued on up. Suddenly he tensed. The answer to his own secret question had come! The law of increasing velocity was at work here. The shapeless hulk that had once been a man formed a terrible and startling clew.

Agent “X” turned, went back into the building. The guard thought he was following Detective Curry.

But Agent “X” didn’t go to the elevator. He didn’t want even its operator to see him. What he had to do must be done alone. Swiftly for a man who appeared as old as Balfour, he began ascending the building’s stairs, going cautiously when he reached the fourth landing.

A light shone in Darlington’s office. Curry was there, searching for a possible suicide note. Eyes glowing brightly, Secret Agent “X” crossed the corridor and continued up. He was convinced that Curry would find nothing. He believed he knew the answer to the state of Darlington’s body. He had seen other men fall — seen them afterwards.

FLOOR after floor he ascended, winding his way up through the building’s interior. Once he tiptoed softly to pass the open door of an office where a scrub woman labored. Once he heard the voices of a group of late workers standing by the elevator. He continued to the building’s top floor. This was dark and deserted. There were two vacancies in it, and two offices that were occupied, but they were closed for the day.

Moving stealthily as a shadow, Agent “X” found a stairway that led to the roof above. It was a metal door and it was unlocked. Agent “X” tensed.

A flight of iron stairs led to a skylight. He climbed them quietly, examined the skylight. This, too, was unfastened and he pushed it slowly up.

A blast of cold night air struck his face. Overhead he saw the clear, brilliant twinkle of the stars.

He closed the skylight, stepped out on the tarred roof. It was broad and flat with a strip of coping around it that made a border of shadow black as jet. The roof seemed as big as a field. Two or three ventilators thrust up starkly, standing like still, watching figures.

Agent “X” stared alertly about him, but could see no movement. All seemed quiet.

Like a man unsure of his ground, he stole forward. His feet made no noise on the black tarred surface. He came to the edge of the coping, looking over.

Far below he could see the spot on the sidewalk that was a man’s body. Darlington! The guard was still there, too, and other figures were moving up.

Rising through the walled canyon of the street in a weird and mournful moan came the siren of an ambulance.

Agent “X” turned away. His eyes were like steel points. There were uneasy prickles along his spine, a warning of danger.

He had his flash out. With its pencil-thin beam he began searching the roof. Then he stooped and picked something up.

It was a small brass screw head, knurled at the edges. It was polished, uncorroded — showing that it had been freshly dropped. Even one night of dew would have given it a thin coating of verdigris.

A little thing, but to Agent “X” it was concrete evidence that he had been right. The thing in his hand was the screw of a camera’s focusing adjustment.

Darlington hadn’t fallen from his window. He had been up here. His researches had led him to the building’s roof. And from this height his body had rocketed down.

Agent “X” recalled that empty case he had seen in Darlington’s office — the case he had felt certain belonged to some sort of camera. The camera wasn’t on the sidewalk. It was nowhere on the roof. It had disappeared completely — and this, coupled with the small brass screw in his hand was significant to the Agent’s alert mind. It was evidence that Darlington hadn’t fallen or committed suicide — evidence that the man had been pushed off the roof — murdered!

Breathless over his discovery, every nerve alert, Agent “X” probed farther with the beam of his flash light.

Foot by foot Agent “X” continued to search. Then he paused abruptly again. His toe had struck against something. He flashed on his light.

Screwed into the surface of the roof was some sort of socket. It was dark-colored, inconspicuous, almost flush with the tarred covering.

HE searched and found others. They seemed to form a mysterious pattern. They were strung along at intervals of ten feet or more.

Under the inner edge of the coping he made another discovery. A wire ran the length of it. At intervals along this wire electric lamp sockets were fastened to the boarding. Every six feet he found one of them. All were empty.

Down in the street the siren of the ambulance rose again as it bore Darlington’s body away. Echoes reverberated like ghoulish laughter, mocking those whom mystery baffled.

Were these sockets more of the slain crank’s handiwork? Was he in the habit of setting his strange equipment up here and gazing at the stars by night?

Somewhere in that string of sockets showing under “X’s” flash like challenging, unwinking eyes was the answer — the solution perhaps of the terrible Flammenwerfer murders. For the death of A. J. Darlington seemed to link up with those other horrible killings at the bank.

But Agent “X’s” investigations were suddenly, rudely interrupted. He was following the coping, heading toward the spot where it angled away along the west side of the building. The two sides formed a dark corner.

So quickly that “X” was caught off guard, a shadow detached itself from this pool of blackness, bounded toward him. He tried to swing his flash as he heard the scrape of feet on the tarred roof, but a balled fist knocked it from his hand. A man tried to dash by him, and Agent “X” leaped in and grappled. He realized then that someone with a coat drawn up to hide the whiteness of his face had been squatting in that corner all the time.

The man was big, powerful. He fought with savage ferocity to break away. The Agent couldn’t see his features — the roof was too dark — but Agent “X” had an uncanny sense that he knew who it was.

Locked like boxers in a clinch they fought desperately, exchanging short, swift body blows, swaying and panting. The movement of their feet made a dry scuffing on the roof. They lurched to the right, edged nearer the coping.

The big man whose face was hidden gave a harsh cry of fear. Agent “X” tensed and pressed his body back. For, in a fleeting instant of horror, he saw the lighted streets below him. They were battling close to the coping, their torsos hanging over.

Repeating his cry “X’s” assailant jerked away. Terror gave him frenzied strength. Agent “X” was unbalanced, pulled forward away from the coping. He toppled through the air, crashed to the dark roof, and the black upright finger of a steam-escape pipe struck against the side of his head. For a moment his body went limp and it seemed that the sky was settling upon him, dropping with a rush and a roar that threatened oblivion.

Chapter XIII

FOR painful seconds he seemingly battled to hold the sky at bay, to keep the stars from burning him. He struck at them, felt them burst and fly off like sparks from an emery wheel. Then he came to his senses.

He was lying on his back on the cold roof. Something slammed somewhere. It was the skylight cover. He tried to rise, fell back, then got groggily to his feet. For the first time he became conscious that he was gripping something. It was small and round and hard.

He saw his flash light case gleaming ten feet away, staggered over and recovered it. He clicked it on and looked at the thing in his hand.

The muscles along his hunched shoulders grew rigid. His eyes became bright. For the thing he held was a pencil with a metal clip. It was painted blue and red. There were no initials on it — nothing extraordinary about it — but the Agent knew he had seen it before. He had an uncanny memory for details, seldom forgot anything that had once registered.

The pencil belonged to Agency Detective George Banton.

Leaving the roof he descended the building’s many stairs rapidly. He saw nothing of Banton, and the fourth-floor offices of the detective agency were dark. Agent “X” hurried to the street.

For an instant his gaze swivelled along the sidewalk. There was still a dark, ghastly stain where Darlington’s body had fallen. He shuddered and the lights in his eyes became bright as polished steel.

At a pace rapid for a man of the apparent age and dignity of Andrew Balfour, he set off up the street. Three blocks away his roadster was parked. He got in, drove to the nearest of his hideouts, and made a rapid change of disguise. When he reappeared this time he was dressed as a young and dapper man — derby hat, trim dark suit, topcoat — a man who would be presentable anywhere without attracting particular attention to himself.

He sped to Detective Banton’s home address listed in the telephone book. It was a luxurious apartment in an expensive section of the city. There, confident of his disguise, Agent “X” asked bluntly to see the detective, ready with a pretext for his visit that would allay Banton’s suspicions. But an attendant in the foyer informed him that Banton hadn’t been back all evening.

Agent “X” turned away abruptly. Banton was the hottest lead along that trail of death and terror. But there were other channels of investigation open. To burrow in from all angles until the crimson edges of the crime picture were complete was the Agent’s method. And time was precious. He would return to Banton later.

His next point of investigation was the home of Jerome Davis, murdered banker. With Davis dead and Mrs. Davis still in Europe, there should be no one there but the servants.

A daring plan came into Agent “X’s” mind. It was imperative that he learn more if possible of the banker’s connection with Rosa Carpita. Then he might discover why Rosa had engaged Banton.

Agent “X” parked his car a full block away from the Davis home, approaching the house from the opposite side of the street. Caution had become instinctive with him.

He crossed the pavement, slipped through a hedge, and circled the house. A dog growled somewhere. Agent “X” paused. Then he sounded his strange, melodious whistle. It was faint now, too faint to reach those inside. It was meant for the dog’s ears alone. The dog’s growling, which had been about to burst into a bark, ceased. Agent “X” saw the twin phosphorescences of the animal’s eyes. The dog was coming toward him stiff-legged, inquiring.

Agent “X” made a clucking sound in his throat. He stood waiting for the dog, then gave his low, strange whistle again. The animal approached, sniffed, wagged its tail. In a moment he was patting the dog’s head and the two of them were on the best of terms.

There was a dim light in the vestibule of the house, another in the kitchen. Coming close to a window, Agent “X” saw a middle-aged couple sitting forlornly at a table. These appeared to be the only servants.

THE upper floor of the house was dark. A porch roof on one side of a rose trellis leading up to it offered a way of access. But, with the couple preoccupied in the kitchen, Agent “X” took an easier course. He quietly and swiftly ascended the front steps, produced one of his delicate pass-keys, and in a moment was inside the house,

The dog, whining softly, tried to follow him. Agent “X” smiling shook his head and motioned the animal back. He left the beast squatting on its haunches puzzled as to why it couldn’t enter the house with its new-found friend.

On rubber-soled shoes Agent “X” crossed the front hall of the house and climbed the stairs.

Investigation of the five bedrooms on the second floor soon revealed the one Davis had occupied. There was a set of golf clubs in a man’s clothes closet. Just off the bedroom was a den. The probing beam of the Agent’s flash light went eagerly into this, disclosed an easy chair and a heavy mahogany desk.

He began examining the desk drawers. Would Davis keep letters from another woman in the house where his wife might find them? Possibly, considering that Mrs. Davis was away now. Then “X” stooped eagerly. Built directly into the heavy desk was a small safe.

He got down on one knee, put his ear to the safe, and moved the dial gently. His ability to discover the combination of a safe by hearing and touch alone was uncanny. In less than five minutes the small door of the safe swung open.

There were letters inside and confidential reports. He went through them quickly, selected two letters with feminine handwriting on them. They were brief notes from Rosa Carpita, accepting luncheon dates. A third, written several weeks later, showed that her friendship with Davis had progressed. He had invited her to take a ride in a plane with him.

Agent “X” put the letters in his pocket. Then suddenly he started. His ears had detected a sound outside. It was the abrupt, low growling of a dog. He closed the safe quickly, strode to the window. The growling stopped as he listened, ending in a strange little yelp of pain. Then all was quiet.

But the Agent, staring out of the dark room, saw a flitting shape cross the lawn below. He saw the figure pause, stare up at the house. It was a man.

Agent “X” waited. The man suddenly and surprisingly began to climb the rose trellis under Davis’s window. A bleak look came into the Agent’s eyes. His pulse beat faster. He tip-toed out of the den, went behind a screen in the farthest corner of the bedroom, and waited there, gas gun in hand.

Seconds of tenseness passed. Something moved by the window. There was a faint scrape, a squeak of wood, then a snap. The window was raised, and a bulky form stepped into the room.

Agent “X” could hear the man breathing heavily after his exertions. All was silent in the house. The man turned on a flash, swivelled it around the room. Then he walked cautiously toward the door of the den.

As the light from the man’s flash fell on the wall ahead of him, Agent “X” got a glimpse of his silhouette. He tensed and held his breath. The man was no ordinary burglar. He was a gross, thick-necked figure. He was Private Detective Banton!

THE Secret Agent watched to see what Banton would do next.

In a moment he found out. The detective, too, made the discovery of the safe in Davis’s desk. He twirled the dial for a moment, then drew something from inside his overcoat. It was a leather kit of safe-breaking tools. Banton put a pair of gloves on, selected a diamond-pointed drill, and bored a series of holes around the lock. He probed and pushed with a metal pick through these holes.

At the end of half an hour, with prodigious sweating and labor, he succeeded by main strength in doing what the Agent had done by skill and knowledge.

With the safe finally open, Banton seemed shaken and nervous. He stopped to listen, fearful apparently that he would be caught in his act of safe-breaking. He didn’t wait to go through the papers in the safe. He began stuffing its entire contents in the deep pocket of his overcoat.

Agent “X” catted silently from behind his screen, crossed to the corridor door, and slipped out. Swiftly he descended the stairs, crossed the front hall, and left the house as he had come.

He moved around it toward the rose trellis, stopped. His foot had touched something. For a brief moment he bent down and flicked on his flash. Then he scowled and muttered harshly.

The dog that he had made friends with a short time before lay stunned at his feet. Banton had silenced the animal by a cruel blow on the head with a blackjack. Gently Agent “X” stroked the dog’s silky ears and soft muzzle. He wished he had time to stay and revive the animal, but there was already a faint sound above his head. Banton was coming out the window.

Agent “X” crept into the shadows of a hedge. There he waited tensely. The bulky form of Banton appeared as a dark blotch on the roof, came down the rose trellis, crossed the lawn. Agent “X” followed.

When Banton had gotten a block away from the Davis home he moved with the confidence of a man who is satisfied with the job he has done. He walked two blocks, got into a little closed flivver, and drove off. The Agent sprinted for his own car, climbed in, and drove along a street paralleling the course Banton had taken. Then he swung toward it, saw Banton’s flivver pass, and followed it.

Banton went first to his own apartment. Agent “X” waited outside tensely. The fact that the detective had left his flivver parked at the curb directly in front of the building indicated he was not through with his nocturnal prowlings. The car, shabby like his clothes and out of keeping with his evident prosperity, was a means of remaining inconspicuous.

In twenty minutes Banton reappeared and drove off. This time Agent “X” stepped out of his hiding-place and signaled a taxi cruising past. Banton might become suspicious if he saw the same roadster behind him again.

The chase led across town and Agent “X” ordered the taxi to slow up when he saw Banton’s flivver stopping. Banton got out, looked around once, then moved off, walking on the balls of his feet with the pussyfooting gait of a professional sleuth.

He turned into a dark side street, moved more slowly. Agent “X” stayed as far behind as he dared and kept to the shadows. Banton looked uneasy. He slowed down still more. Suddenly Agent “X” tensed.

A figure stepped out of a doorway and joined Banton. It was the figure of a girl. She took Banton’s arm and they moved off together. Agent “X” crossed the street and followed them.

They continued for two blocks and entered a small Italian restaurant. Agent “X” strolled by and looked in. Then he nodded to himself and his eyes gleamed. The girl who had met Banton was Rosa Carpita.

She hadn’t left town after all. She was in hiding, and, far from her regular haunts, she had met Detective Banton by prearrangement.

Agent “X” meditated a moment. He wanted to hear what they were saying, just why the girl had engaged the professional services of Banton, but it was important, too, that he find out where she lived. In the restaurant it would be impossible to use his microphone. They might become suspicious if he took a table too near them.

He engaged a taxi and had it wait around the corner, heading into the street the restaurant was on. Then he took up a position where he could watch the front entrance. His nerves and brain cried out for action, but this was a situation that called for patience and care.

It was a long wait, nearly an hour, before the two reappeared. They parted at the door of the restaurant, Banton going one way, the girl going the other. This meant that they had concluded their business, whatever it was.

THE girl set off on foot. Agent “X” paid off his disgruntled taxi driver for the time spent in waiting. He himself followed the girl on foot, shadowing her to a shabby, low-class hotel, five blocks from the restaurant. It was very different from her own swanky apartment, proving that the girl was taking no chances of being seen by anyone she knew.

He waited till she had passed through the lobby and had taken the old-fashioned elevator upstairs. She must have checked in here that very day.

Leaning over the desk, Agent “X” made inquiries as to rates in the hotel. As he did so he stared at the register. The only entry of a single party made that day was “Marie Rosa, Washington, D.C.” The Agent nodded with a faint, grim smile on his lips.

He thanked the clerk for his information, then turned and left. A plan had come to his mind. Now that he knew Rosa Carpita’s whereabouts and had seen her in close confab with Banton, he might go to her disguised as the private detective. But first he would have to learn from Banton himself some inkling of what their business was.

He took a taxi to the block where he had parked his own roadster, and headed back toward Banton’s apartment, devising alternate plans according to whether Banton was in or out.

Almost mechanically he sent the powerful car racing across town, his mind battling with the hideous murder mystery that was costing men’s lives.

Suddenly the Agent turned his head. The high-pitched wail of a police siren sounded. He drew toward the side of the street. A green radio patrol car shot past, going like the wind.

There was a frenzied note in the blast of its siren, recklessness in its speed. Wrenching the wheel, the Agent turned and followed. He heard another car join the first, racing in the same direction. A crawling sense of horror filled him. A hunch told him it could mean only one thing. The torch-killing band of robbers had struck again!

Chapter XIV

CROUCHING over the wheel, he pressed the gas button down until his own long, low roadster was eating up the distance that separated it from the nearest radio cruiser. The red tail-light of the police car increased rapidly in size.

It was headed toward the mid-section of the city. Then brakes squealed in sudden protest. Rubber snarled on the pavement. The cruiser was slowing down.

Agent “X” saw why. Down the block another car was coming — a long, low roadster with a narrow windshield and flattened hood.

In his first horrified glimpse of it, Agent “X” recognized the car. It was the same one that had followed him when, disguised as Commissioner of Police Foster, he had nearly lost his life with Inspector Burks. Its terrific rate of travel indicated that it was speeding away from the scene of some other crime.

Agent “X,” a cold chill clutching at his heart, wished he could cry out a warning to those cops in the car ahead. He tried to do so, but they didn’t hear him. Then he jammed on his own brakes, watched like a man in the midst of a nightmare over which he has no control,

One of the cops in the cruiser thrust a submachine gun out of the vehicle’s side, pressed a trigger, sending a stream of bullets toward the oncoming roadster. But it was a speeding target no man could hit.

It careened toward one curb, leaped back toward the other, came roaring on. Suddenly the Agent’s knuckles went white on his own steering wheel. A wicked black snout poked out of the roadster’s side-curtain. There was a hiss, a streak of light through the air, and a blinding, crackling jet of flame played over the police cruiser that had tried so staunchly to bar the murder car’s way.

The cruiser, still moving, swerved and crashed into the curb. The cop with the machine gun tumbled out as the door burst open. He fell on his knees on the sidewalk, and the roadster roared by, its hideous weapon playing over the cruiser, killing the cop at the wheel, making a funeral pyre out of the trim headquarters car. It was gone up the block at express train speed before the fallen cop could arise.

Agent “X,” trembling, slid into the curb behind the burning cruiser. The man inside was dead, beyond aid. The cop with the gun was just getting up. Agent “X” called out harshly and made a quick motion.

The cop hesitated only an instant, his face as white as parchment. Then he understood. He leaped onto Agent “X’s” running board, and even as he did so, “X” sent his own car forward with a screech of quickly meshed gears.

The cop was silent as “X” hurtled ahead. The engine under its polished, streamlined hood rose to a vibrant roar of power. The clack and hiss of the tires made talk impossible. The Agent’s eyes were focused far in front. He passed a police cruiser, outdistanced it. His knuckles were white, his eyes gleaming points of steel. For the moment he was acting on impulse. In a cold, unreasoning fury, now, he was doing the one thing that seemed possible, chasing the killers, hoping to give the cop with the gun another chance to use it.

Driving as he had never driven before, driving like a madman, he sent his roadster hurtling through the night-darkened streets. Then far ahead he saw the murder car. There was, he knew, some special motor under its low hood. His own cars were custom built, bought for the highest speed, the most exceptional usage. Pressing the gas button to the floor boards, risking death every instant, he crept up on the car before him.

The street no longer seemed like a street. It was a whizzing, hissing band of black asphalt, ripping back under the tires, threatening, it seemed, to tear them from the rims.

The cop beside him leaned out the side of the car. He was shaking, his face was deathly white. But his hands were holding the submachine gun steadily. The department heads might be getting nervous, losing their morale, but these men in blue were fighting like true soldiers. Agent “X” warmed to the man beside him. For the moment he was proud to be battling shoulder to shoulder with the law which had so often hunted him.

HE was gaining on the murder car now. The suburban streets were flashing by. Houses seemed to leap at them out of the darkness. In a moment he heard the stuttering report of the machine gun in the cop’s hand. An acrid whiff of smokeless, powder filled his nostrils, lashed back by the wind. The ejector of the gun was spitting empty shell cases.

Then with breath-taking suddenness the murder car seemed to be coming toward them. Agent “X” knew what it meant.

He applied the brakes, shouted a warning to the man beside him. He wasn’t thinking of his own life. But nothing would be accomplished if the killers in the car, now slowing down, were allowed to slaughter again.

Then, in the air directly ahead, shutting out view of the murder car, blinding like a blazing sun of death, appeared a fiery eye of flame. The cop swore fiercely. The jet of flame came nearer. Its heat was scorching. In another instant it would be upon them. The cop flung down his gun and jumped.

Agent “X” crouched, jammed on the brakes. The sickening smell of scorching rubber filled his nostrils. The front tires of the car blew with reports like miniature bombs. The roadster bumped and sagged on tire rims. He opened the door, flung sideways, just in time.

The jet of flame descended on the car, melting the windshield as though it were a sheet of ice, firing the padded leather cushions inside. With the cop beside him, “X” raced for the protective shadows beside the street.

The murderer’s car drove on, leaving Agent “X’s” roadster a burned and ravaged wreck.

Crouched in the chill darkness, waiting for the other radio cruisers to come up, the cop told Agent “X” what had happened.

“I don’t know you, buddy, but you got guts,” the cop said. “We didn’t get ’em — but we tried. They blew the safe of the Graybar Jewelry Company and got away with a half million in ice. They burned the guard, just burned the guy, too. Schroder and me got it over — the guy that was driving me, a good guy, too. Schroder and me got it over the air from headquarters and tried to head ’em off. But a swell chance a fella’s got against that heat gun they use.”

Agent “X” nodded somberly. A direct attack against the torch killers was suicidal. His face was bleak in the wavering glare of his burning roadster. He heard other motors down the block — radio cruisers coming. The murder car had sped on — no one knew where.

Cold fury at the killers possessed him. He didn’t wait for the cruisers to come up. There would be questions, delay. He wanted to get back to the city, back to his own line of investigation at once. Without any explanation to the surprised cop he flung off into the shadows and disappeared.

He crossed a lot, put two blocks between himself and the light of his burning roadster, then he located a taxi. The police would have another mystery to probe as to the owner of the burning car. The name it was registered under would tell them nothing. There was no such person.

Agent “X” sat still and tense as the cab sped back along the route over which he had pursued the murder car. The night had been a chain of apparently unprofitable episodes. But he had gained something — learned the whereabouts of Rosa Carpita, and caught Banton in strange actions. Banton!

“X” leaned forward, spoke to the driver. The cab stopped in front of the private detective’s apartment. It was late, getting close to midnight. Banton’s flivver wasn’t outside the building. “X” hoped the man was in. He would have some sort of show-down. There must be an end to these death-torch horrors, and, if Banton knew anything, “X” would find a way to make him talk.

He located Banton’s suite number in the mail slot and went directly up, letting himself into the building with a pass-key. The switchboard operator merely glanced at him as he passed by, thinking he was a tenant or the friend of a tenant.

AGENT “X” pressed Banton’s buzzer and waited. But there was no answer. Banton was out. Unceremoniously, then, Agent “X” entered.

The apartment was small, unattractive, cluttered. He searched with the thoroughness of a trained investigator, worked with the frenzied speed of a man driven on by a single motive. But the results of his search were disappointing.

He located a safe, opened it, and came upon the papers Banton had stolen from Davis’s house. There were also records of Banton’s more shady transactions for various clients. But there was nothing which threw light on his dealings with Rosa Carpita. That must be gotten from the man himself. There were two courses open to Agent “X.” To wait here for Banton’s return, or to go in search of him.

Agent “X’s” nerves cried out for action. It was possible Banton had gone back to his office. He could make the trip there, then return if he failed to locate Banton.

“X” went to the nearest of his hide-outs and changed back to the disguise of Andrew Balfour. As he drove in a cab to the bank building he mapped out a course of action.

“X” left his cab and walked swiftly to the side door of the bank building.

He entered with his tenant’s key, ascended quickly to Banton’s office. But it was dark and empty. “X” let himself into his own suite, then switched on the lights and paced the floor, thinking.

He hated to involve Betty Dale in any way. Yet in the present situation she could help him. It would be easier for her than for him to check up again on the movements of Rosa Carpita. He knew that Betty, as always, would be willing to aid him, and, late as it was, he didn’t hesitate to call her.

But, as his hand reached out for the telephone, he paused. Faintly through the thick walls of the room a strange scraping sounded. Another man might not have heard it. But the Agent’s hearing was uncannily keen. The scraping noise was followed by a thud that was hollow, ghostly. The Agent leaped to his feet.

He strode to the door, opened it, thrust his head out and listened. Banton’s office was dark, but once again he heard the eerie scraping. It filled the corridor with a thin whisper of sound, faint as the rustling of a serpent’s scales sliding over stone. It set his teeth on edge. Then the noise ceased.

The Agent stood puzzled a moment, went to the door of Banton’s office and let himself in with a skeleton key. Tensely he searched the place, but no human thing was there.

He went back to his own office, got out his sensitive sound amplifier and pressed the disc microphone to the wall. Then he trembled with excitement. A turn of the rheostat control and the scraping sound reached his ears again. It seemed to be on the floor above now, or even higher. With a sudden hiss of breath the Agent put his amplifier down. He leaped into the corridor and started at a run for the stairs that led upward.

Chapter XV

THERE were many of them. The building towered sixteen stories above the floor his own office was on. But he dared not use the elevator, dared take no one into his confidence. There were secret and sinister things in the wind.

He climbed the stairs three at a time, floor after floor. Near the top he paused an instant to rest and listen. He no longer heard the scraping noise. The great building was still. But gradually as he waited a new sound intruded upon his consciousness. It was the muffled, far-off beat of an airplane motor, and it seemed to be approaching. Once again the Agent was electrified into action.

He took the last flight of skylight stairs in a reckless leap, crouched tensely. Then, as he cautiously raised the glass cover, he heard again the faint deep-throated mutter of a plane somewhere in the dark sky overhead.

The cloud ceiling was low. Swirling, trailing vapor threatened wind and rain. The glow of the streets was reflected in this mist. The ship above seemed to be nosing down through it, feeling its way. Perhaps it was only a mail plane, perhaps—

But Agent “X” strained forward. His gaze left the clouds, went to the roof. His eyes grew wide with intent interest.

There were times when his swift actions were based on so-called “hunches”—really the quick interplay of deductive faculties working below the conscious level of his mind. It was such a hunch, such a subconscious deduction, that had made him suspicious of the sound in the wall and brought him up to the roof. And it had not led him wrong.

For the roof had undergone an amazing transformation. From the under edge of the coping on each side a bright glow of light was now flaring out — light from bulbs, the sockets of which he had discovered on his previous visit.

And, from the roof’s center, set in the strange socket clamps, was a collapsible framework of slender tubular steel.

There was a pulley, a sliding truck, a spring releasing device — with something set in a metal holder that caught and held the Agent’s eye.

The thing was a big canvas sack like a mail pouch.

In one rushing, clear-visioned flash of understanding the Agent grasped the significance of what he saw. It linked up with the strange death of Darlington, and brought him one step nearer to the death-torch killers.

The device in the center of the roof was similar to that used in airmail pickup. The airplane circling overhead, feeling its way down through the low clouds, was coming to get that sack. What the sack contained, Agent “X” could guess. The crank, Darlington, had been murdered because, in his lonely studies of light, he had come up to this roof to look at the stars, photograph them, perhaps, and had accidentally interfered with the plans of a fiendishly clever band of thieves and killers.

The Secret Agent leaped forward to the waiting canvas sack. A knotted cord fastened the neck of it. A stout braided wire cable was bolted to a series of metal rings sewed directly to the heavy canvas, sufficiently strong to stand the jerk when the sack was swung into the air after a catapult device had thrown it forward.

The Agent unknotted the cord at the sack’s mouth. He moved with lightninglike speed, knowing that any instant the plane above might swing into sight. The poor visibility, the lowness of the clouds, was all that made possible the desperate thing he planned to do.

Many packages of bank notes were there, and smaller canvas sacks of gold and silver coins. Here was a haul of stolen loot waiting to be relayed to some safe hiding-place — loot that had been taken at the cost of men’s lives.

There were a dozen big ventilators jutting from the roof. With an armful of packages containing bank notes the Agent ran to the nearest of these. Unceremoniously he dumped the cash in. He wasn’t sure where it would fall, but it could be located and recovered afterward. Frenziedly, working against time, he made four more trips, dumping the bags of coins into the ventilator, too, emptying the big canvas sack hooked to the catapult.

He heard the airplane in the clouds above shut off its motor. He knew the significance of that. The ship was getting ready to dive below the clouds, glide in to make its pickup. His experienced ears told him that its motor was muffled, that the pilot was taking no chances of having someone in the street hear him.

With eyes bright as pin points of polished steel the Agent moved close to the sack. The thing he was about to do seemed almost suicidal. It required sheer nerve, fearlessness of death — characteristics that the Agent possessed to an extraordinary degree.

The instant before the plane above broke through the under edge of the clouds, Agent “X” stepped into the sack, replacing with his own body the bulk of the bills and coins he had taken out. The weight was not greatly different. Perhaps he was twenty or thirty pounds heavier. But the sack was big, the catapult device should be strong enough. He hoped so, waiting silently, with the cord he had removed once again looped around the mouth of the sack, its ends drawn inside. He tied them just as he heard the first thin whistle of rushing air sweeping through flat wires.

IT seemed an eternity while the whistle mounted into a wavering screech. Then the pilot of the approaching plane flattened his glide. The screech lessened, became a thin wail. The wail grew steadily louder.

Blood pounded through the Agent’s temples. He could hear the beating of his heart as though it were sledgehammer blows. He had been in many strange and desperate situations, but never one quite like this, when seconds seemed to stand still, when he waited for the grappling cable of the oncoming plane to sweep him into the very jaws of death.

He could hear the clank and swish of the still revolving propeller, like the beat of great ghastly wings. Then there came a click, a snap. The Agent held himself tautly, gripping the cord of the sack mouth in fingers that were white and steely.

Abruptly he toppled sidewise, pressed against the side of the sack. The sack was rushing forward. His neck was snapped back, his head was pressed against the canvas, too, as though a thousand pounds were holding it there. Breath hissed from his lungs.

There was another snap, a nerve-shattering, forward lurch, a dizzy sense of being whirled in an arc as though he were on a giant pendulum. Then a rush of upward movement at express-train speed.

Now he was pressed to the bottom of the sack, glued there apparently, his only conscious hold still on the end of the cord, and the cord was straining into his fingers, cutting them. That upward movement was familiar. He had felt it before, though never like this. He knew he was free of the roof now, sweeping upward into the sky on the end of a slender cable — sweeping with the threat of death imminent.

There was a sudden low mutter of sound, a jarring tremble that the cable transmitted down to him. The plane’s engine had been switched on again. He was yanked skyward at a steady, breath-taking pace. The sides of the sack grew clammy as it was drawn through the clouds.

Then the plane leveled out. There was a metallic grinding sound — the sack being reeled in.

Agent “X” waited. The suspense now was as great as when the plane was gliding in to pick him up. Would the pilot discover the amazing substitution that had been made — a living man instead of a sackful of stolen loot?

The grinding continued. The sack swung from side to side in dizzy, breath-taking sweeps that told of the plane overhead rocking and dipping in a windy night sky. The side of the sack struck something with a cracking blow that almost knocked Agent “X” unconscious.

He gasped, recoiled, felt the top of the sack flattened against a hard surface that pressed down on his neck and shoulders. His face was pushed forcibly into the canvas, but the grinding noise had ceased. There was only the steady vibrating roar of the plane’s motor. The sack no longer swung. It had been snugged fast under the belly of the ship.

For almost a minute Agent “X” didn’t attempt to move. He rested in his cramped, contorted position, breathing in great lungfuls of musty air. The last few seconds had been the most desperate of his entire career. He was still in the shadow of destruction suspended in a canvas sack under the fuselage of a madly racing bandit plane, flying toward an unknown objective.

But he was closer to the killers than he had been since their terrible raids started — closer perhaps to learning the secrets of their fiendish organization.

He began slowly limbering his cramped muscles while the plane hurtled on. The sweeping rocking movement of the tightly clamped sack told him that the air was rough, stirred by stormy winds. Only the lure of gold would have influenced any pilot to make such a daring pickup on a night like this.

THE Agent freed his left hand from the place where it was pinned under his own body. He worked it up toward the top of the sack.

With both hands he tugged at the cord fastening. But it was impossible to undo it, useless even to try, with the top of the sack wedged against the underside of the plane.

The Agent freed his right hand from its hold on the cord. He worked the fingers down to his pocket; fumbled for seconds in the numbing cold that was beginning to seep into the sack in the hundred-mile-an-hour slipstream.

His fingers came out at last holding a jackknife. With infinite effort he succeeded in opening it. Cautiously he drew the blade up until it was on a level with his eyes. He turned it, edged it sidewise, cut deftly through the canvas, making a small peephole. But he could see nothing.

A blast of wind struck his face with the force of some solid substance. He made the hole wider, edged the knife blade down. To stay in the sack in his present position until the plane landed would be suicidal. The killers who had snuffed out the lives of a dozen men would unhesitatingly butcher him.

But he had no definite plan of action. His one thought had been to find where the plane was going, who was piloting it, and to what secret hideout the stolen money was being taken.

He worked the slit in the sack until it was large enough for him to thrust an arm out. Feeling in the icy darkness and cutting blast of the slipstream, he verified what he had already guessed.

The ship was a seaplane, equipped with twin pontoons. It was the same plane from which the bullets had been fired that had shot Rosa Carpita from the skies, killed her pilot. The sack was snugged between its pontoons. He reached up, felt the cable on top. It disappeared through an eyelet in the fuselage of the plane, connecting with a reel somewhere in the pilot’s cockpit.

For seconds he deliberated. The wind blast was getting terrific. The air was growing more and more bumpy. Wisps of chill fog whipping past, beaded his face with icy moisture. What should he do?

HE felt around the mouth of the sack with tense, groping fingers — felt for the rings that were sewed to the canvas. There were many of them; but if the stitching should become loosened, if the sack was gone when the plane landed, its loss would be attributed to the jerking, whipping lash of the wind. And the loss would cover his tracks. First, however, he must get out of the sack himself.

With the blade of the knife he slit the sack from top to bottom, and, regardless of the tearing blast of the wind, slowly crawled out, wrapped his legs around pontoon struts. Minutes passed before he was entirely independent of the sack for support.

Bracing himself in the full blast of the slipstream, with the hungry fingers of Death seeming to reach for him, he began systematically cutting the stitches around the metal rings.

Not until they were free, with no trailing thread whose cut end would tell that a knife had been used, did he stop to rest.

Not until he heard the empty sack whip back between the pontoons and go sailing off into the darkness behind the plane.

Then, braced and panting, he rested after his terrible exertions. Yet it was hardly a rest that a man would choose. For the force of the wind seemed bruising, and the numbing beat of the cold was making him ache all over. There were moments when the lulling voice of Death seemed bidding him to let go — find relief in a swift fall into the dizzy spaces below.

Suddenly he felt the ship’s nose tilt downward. A sensation came like that of going earthward in a fast elevator. A cloud of mist beat up against his face. Holding tightly to the struts, he waited.

Minutes seemed to pass as the plane lost altitude. Suddenly lights showed through the swirling masses of vapor beneath. They were lights stretching in a semicircular ring, lights that the Agent had seen before. This was the harbor over which Rosa Carpita had circled in her hired plane.

The Agent’s pulses quickened. The plane was coming down for a landing. There was purposefulness in the way it was descending.

It swung around in a great bank. The riding lights of ships, the lights strung along the shore, whirled in a strange kaleidoscope of luminescence. The hidden pilot above switched off the engine. For a moment he flicked on a searchlight — the same searchlight whose ruthless eye had picked out Rosa Carpita’s plane in those terrible seconds when her pilot had been killed.

Looking down, Agent “X” saw storm-tossed water. Great swells were coming in from the open sea. The harbor seemed too rough for a landing. The pilot of the engine seemed to think so too. He hesitated, switched on his engine, came nearer shore. But, driven on by the lust for gold, men will do desperate things. The Agent knew this. It was evident that the pilot intended to land.

The Agent held his breath. This killer above him possessed infinite skill. No doubt of that. He handled the little plane like a master. His flying spoke of long experience in the air.

The plane circled again, descended till its long pontoons were almost touching the tops of the swells. The roar of breaking waves mingled with the beat of the throttled motor.

The Agent wrapped arms and legs around struts. Then the plane came down, touched.

To the Agent it seemed to crash with the force of a battering ram. The water seemed to have a rocklike hardness. An icy crest drenched him, battered him. But the plane was only on its first step. It settled still more, nosed into a breaking swell, driven by the gale. A half ton of water smacked against Agent “X.” No man living could withstand it. It tore at his arms and legs. He felt himself slipping. Frantically he clutched, but a second wave followed the first. With a smothered, choking cry the Agent was swept from his precarious hold, swept into the black water as the plane settled to its landing.

Chapter XVI

HIS head flicked a strut as he was swept by. For an instant he fought the blazing, whirling lights that flashed in his brain. Then he struggled with the mountainous seas that seemed to crash in on top of him in glittering cascades. He sank beneath the surface, bobbed up in the wake of a hissing swell.

With numbed muscles and dazed brain he began the battle of his life. The sense that he was drowning spurred him on to fight with the water as though it were a living thing. He’d come too far to go under now, even though it would be easy to slip beneath the waves. Who would be the wiser? No one — but Agent “X” had work to do.

On the crest of a wave he gazed shoreward. The seaplane had disappeared in the blackness, its motor sound sinking to a low rumbling mutter, then ceasing entirely. It was somewhere resting on the water, but he couldn’t see it.

He could see lights along the beach, however, and here and there the riding lanterns of vessels. Sensing the direction of the wind he allowed himself to go as the waves went, in toward the shore, husbanding his strength.

The huge steel side of a yacht loomed out of the darkness, shutting off his view of the shore. It seemed endless as he slid along its length. A single red riding light winked down at him. He might have called for help, but he didn’t.

The plane had landed in this small harbor. Here somewhere was the solution of the terrible mystery of the torch murderers. In this vicinity they had stored their loot. He would not risk his chances of finding them by calling anyone’s help now.

But the last half-mile to shore was a nightmare. Part of the time Agent “X” was half unconscious. He was battered, bruised, swirled by the waves. He felt as though he were swimming along some limitless watery treadmill, climbing numberless swells, descending into the hollows, rising to the top again. The sting of salt spray in his eyes almost blinded him.

When at last his feet touched bottom and he reached the shore, he could only crawl up it on hands and knees. He fell forward on his face, lay still, then heaved himself up again. This wouldn’t do! He mustn’t be discovered here. He struggled to his feet, stumbled up the beach. Then his knees bumped something. He groped blindly until, through smarting lids, he saw the dim bulk of a big shed against a background of light beyond.

He moved along it until his fingers found a door. It seemed loose, and, tugging against it, he found that it slid back on rollers. The air inside was warmer. It was heavy and musty with the scent of twine and tar. He sank again to his hands and knees, groped, and his fingers encountered a pile of old sails. On the rough canvas, with the wind shut out, he sank into exhausted slumber.

THE cold, gray light of dawn was filtering into cracks in the sail shed when Agent “X” awoke. He had the remarkable faculty of sleeping as soundly as a child when he slept at all, and of restoring weary nerves and muscles. In spite of his wet clothing and the exhaustion of a few hours before he stretched, rose, and felt fit again.

With quick, cautious steps he strode to the wall of the old sail shed and looked through a crack. A stretch of cold, gray harbor with boats floating on it met his eye. But the seaplane was nowhere in sight. For a moment he stood debating.

He knew that, wearing the disguise of Andrew Balfour, he must be an incongruous sight. The salt water had ruined the shape of his suit. Wet and wrinkled it was draped around his body. But, so perfect was the material used in his facial make-up that even the submersion hadn’t washed it off.

He was still Andrew Balfour, still the middle-aged business man — but a man in appearance very much the worse for wear. If he were seen around here it might arouse the suspicion of the very people he didn’t want it to. He couldn’t say who they were. But he was certain now that the hiding place of the stolen jewels and currency that the torch robbers were taking in their wholesale banditry was somewhere around here — perhaps on one of the yachts.

That was the most logical place for it, and it instantly gave him an idea, a plan of action. But first he must get away and change his disguise.

He walked to another wall of the shed, looked along the shore. There were many bungalows and cottages, closed because of the earliness of the season. Smoke rose from the chimneys of a few built for all-year-round use. But no one was in sight. He judged it was still very early in the morning. His watch had stopped.

He opened the door of the shed, slipped around its side, and, keeping it between himself and the harbor, walked inland as fast as he could. Not until he got five hundred feet away from the water did he spy anyone. Then he saw a sleepy-looking milkman making his rounds. He ducked out of sight till the man and his horse and wagon passed by. There was a trolley track, but no trolley seemed to be running. The Agent wanted to get away from here as quickly as possible. But how?

There was no way out except to borrow someone’s car. It could be returned later. He saw several parked before houses along side streets. One was in front of a hedge, hidden from the windows of the house. It was a touring car with the side curtains down. The ignition was locked, but Agent “X” quickly raised the engine hood, found the ignition wires, broke them off, joined their ends together, and established a circuit.

While the people in the house still slept he got into the car and drove off rapidly. He could leave it anywhere, and the police, through the Motor Vehicle Registry, would see that it was returned to its owner. To catch the band who had taken the lives of over a dozen men, Agent “X” felt he was justified in commandeering this car.

Back in the city, in one of his own hideouts, he changed his disguise to that of Elisha Pond, the mythical character in whose name a vast sum of money was on deposit in the First National Bank.

When the bank’s doors opened at nine Agent “X” presented himself at the paying teller’s window and drew out ten thousand dollars, asking mainly for bills of large denomination. The bank was accustomed to the eccentricities of “Mr. Pond.” His account was of such size that all employees had been instructed to be especially respectful.

With the money in his possession, Agent “X” made another quick change. He put on a suit of expensive, sports tweeds, molded the lines of his face into the appearance of a well-groomed, well-fed, prosperous-looking bachelor in his late thirties. He placed a handkerchief in his upper coat pocket, the corner showing jauntily, put a huge solitaire diamond ring on his finger, and selected a Malacca walking stick. Attired thus, he set out again.

IT was nearly ten. He called Betty Dale and asked her as a favor to him to keep an eye on a certain Marie Rosa, registered in a down town hotel, the address of which he gave.

He next called up the offices of “Andrew Balfour” and told his office managers that he expected to be out of town for part of the day. He considered dropping in on Banton, but gave up the idea as profitless. First of all he wanted to establish a base at the yacht harbor from which he could operate without arousing anyone’s suspicion. To do that he was prepared to splurge on a grandiose scale.

Under the name of K. K. Parker, one of many aliases he was accustomed to using, he hired a large limousine and chauffeur for a week, to be at his beck and call whenever he might want them.

In this handsome vehicle, reclining on the soft cushions, Agent “X” drove back along the suburban roads to the yacht harbor where he had so nearly met death a few nights before. His eyes were hard and bright as he stared through the speeding limousine’s crystal-clear windows. A glow of excitement filled him as the harbor came into view.

Sunlight was breaking through the clouds now. The water was blue and sparkling. The storm winds were subsiding, but, to Agent “X,” that bright expanse of water held sinister significance. There somewhere, killers lurked. There loot that had been paid for in men’s blood was hidden.

As K. K. Parker he had his limousine draw up before the office of the town’s boat works. A sign in the window read: “Reconditioned Yachts For Sale.”

Smoking a cork-tipped cigarette, Secret Agent “X” strolled into the office and presented his card. “I’d like to look over some of your boats,” he said.

His name obviously meant nothing to the manager of the shipyard, but the limousine standing outside, the cut of Mr. Parker’s clothes, his appearance and commanding air were impressive.

The manager nodded, spoke deferentially. “Come this way, sir, I’ll show you what we have.”

On this lengthy tour of inspection the Agent asked endless questions. What was the seaworthiness of this boat, the speed of that, the fuel oil consumption of such and such an engine.

At last he located a craft that seemed to please him. This was a large cabin cruiser that had formerly belonged to a millionaire shoe manufacturer. The Agent paid a five-hundred-dollar option on the vessel, announcing that he intended to arrange for certain alterations and redecorations. The manager didn’t know that the man who called himself Parker was interested in the cruiser solely because of its position.

From its portholes Agent “X” could command a view of the harbor in both directions. With a pair of compact, high-power prism binoculars he read the name on every yacht within sight. There were nearly a dozen drawn up beside piers, covered over as this one had been. These drew his particular attention.

Having established a base to which he could come unmolested and without rousing anyone’s suspicions, Agent “X” started back for the city early in the afternoon. First he put in a long-distance call to Betty Dale.

Her answer wasn’t too satisfactory. The girl, “Marie Rosa,” or Rosa Carpita, was still registered at the hotel where Agent “X” had seen her, but she had slipped out before Betty had got there and had not been back as yet. Her luggage, Betty had ascertained, was still in her room.

Frowning, Agent “X” went back to his parked limousine. The patient chauffeur backed the car around, headed for the road that led to the city. But he had gone only a mile when Agent “X” barked abruptly into the speaking tube. His eyes, looking out of the car, were suddenly steely with alertness.

“Stop,” he said. “Turn around and go back.”

The chauffeur nodded glumly. The whims of rich men were never very understandable.

But it wasn’t a whim that had prompted Agent “X’s” sudden change of plan. A small flivver was parked in a side street. Agent “X,” who missed nothing down to the smallest detail, had got a glimpse of the car’s license plate. It was the flivver belonging to Private Detective George Banton.

Chapter XVII

AGENT “X” spoke to his chauffeur as the car approached the harbor town’s central parking space.

“Stop here,” he said.

At a swift stride he struck off along the street. But, once out of sight of his chauffeur, he went back toward the spot where he had seen Banton’s car. The car was empty. The side curtains were down. Agent “X” touched the motor hood. It was cold. This meant that the flivver had been parked there for some time.

The side street in which it stood led up toward the summit of a small hill overlooking the harbor. Summer bungalows on wooden foundations lined each side of the street. They appeared to be empty.

Flicking his cane, smoking a cigarette, and strolling like a stranger looking over the town, Agent “X” walked up this hill. When he reached its top he ducked out of sight between two deserted cottages. Peering through a screen of leafless bushes he stared in both directions. The harbor lay peaceful at his feet, dotted with yachts at anchor. A path led along the shore to another cottage colony on a neighboring hill.

Agent “X” waited, watched, then raised his small, powerful glasses to his eyes. He might have been a rich sightseer looking over the yachts in the harbor. But he turned his glasses away from the harbor toward the many bungalows. For minutes he searched, then suddenly tensed.

On the side porch of a bungalow a quarter of a mile distant were two figures — a man and a woman. He caught sight of the woman’s head first. It was heavily veiled. No features were visible, but the set of the head, the carriage, were familiar to Agent “X” who noticed such things.

The man’s face came sharply into focus. It was Detective Banton. And the girl with him, “X” was certain, was Rosa Carpita. He became more certain as the girl touched her companion’s arm and said something. The lithe swing of her body, the studied poise of her which had become unconscious and instinctive, gave her away in spite of the heavy veil.

They, too, were looking out over the harbor. But “X” saw that the porch on which they stood was screened by a low bluff with bushes on the top. Only their heads would be visible from the water. They didn’t want to be seen.

Excitement tingled through Agent “X’s” blood. Step by step he was creeping closer to his goal. Two of his chief suspects were here before him. Somewhere out on the blue harbor was one of the bases of operations of the torch-murdering band. His face set grimly. He must move cautiously now. Everything depended on stealth and strategy until he was sure of his ground.

When he saw the two on the bungalow porch leave at last and start back toward the hill on which he stood, he preceded them down the narrow street. He went back to his own car, got in, and told the chauffeur to drive slowly ahead and stop. Not until he saw Banton’s flivver back out of the side street and head toward the city, did he give further instructions.

“Keep that car in sight,” he said, “but don’t get too close.”

The shadows of afternoon were lengthening into evening. Banton’s little flivver was making good time, lurching and bobbing over the road. Agent “X” felt secure in the belief that his own presence in the limousine with the chauffeur would not arouse suspicion.

WHEN they reached the city, Agent “X” considered whether to follow Rosa Carpita or Banton. He was certain they would separate, and he decided on the latter. Betty Dale would keep watch of Rosa Carpita’s movements for him. Banton seemed the more sinister.

He was right about their separating. Rosa Carpita got out in a dark block and hurried off. Banton continued on to his office in the bank building. Agent “X” drove by in his limousine, then dismissed it, telling the chauffeur he would not be needed until the next morning. At a brisk stride Agent “X” went to the nearest of his hideouts.

He changed quickly to the disguise of Andrew Balfour and hurried to his office. In his pockets this time he secreted many strange objects — not knowing what emergencies he might have to meet in the next few hours.

The girls were just leaving his office, their day’s work done. He nodded to them curtly and went to his own sanctum with the air of a man preoccupied with weighty business matters. But when the last of his help had gone, he tiptoed quickly to the door and peered out into the corridor. As he stood watching he saw two of Banton’s assistants go into the private detective’s office. In ten minutes, two more arrived. There seemed to be a gathering of the clan.

Banton had evidently summoned them. What for?

Agent “X” was glad he hadn’t been able to locate Banton the night previous, directly after seeing the flaming torch murderers kill another cop. At that time he had been all for bluntly approaching Banton and making him talk. Now, calmed down after his strange experience of the night, he was ready to use caution and strategy again — ready to look first and leap afterward.

When another of Banton’s sinister-looking aides had come, Agent “X” saw the detective’s shadow on the frosted glass of the door, heard the click of the lock. Banton had assembled his men for a secret conference.

Agent “X” worked quickly. People were passing by in the corridor every few minutes, leaving their offices. They would be doing so for the next half-hour. To stay outside Banton’s door listening with the portable amplifier that he had used effectively before, would be courting detection and disaster now. But there was another way.

Agent “X” took a spool of insulated wire from his pocket, wire as black and thin as thread. There were small copper terminals at each end. It was a slender electric cord which he carried for just such emergencies as this — to extend the range of his amplifier.

With the small disc-shaped microphone in his hand he stepped quickly across the corridor to Banton’s door. No one was in sight. He reached up, dropped the microphone through the transom, took a turn of the threadlike wire around one of the transom rods, and then backed toward his own office.

He threw the other end of the almost invisible wire over his own transom and pulled it taut. It now stretched across the corridor, but far above the height of people’s heads. In the semigloom it wouldn’t be seen.

With tense fingers he connected the terminal at his end to the portable amplifier in its cameralike case.

A TURN on the rheostat control and he was listening in on the secret conference in Banton’s office.

It was disappointing in some respects, importantly significant in others. Banton was issuing orders, not giving away secrets. His voice was rumbling, aggressive.

“Don’t ask me why,” he was saying, arguing down an over-cautious aide. “Do as I tell you. That’s your job. That’s what I pay you for — an’ you can’t afford to be choosy. There ain’t one of you I ain’t got something on. I could send you all back to the gutters where you came from — or worse.”

Banton’s sneering laugh sounded.

“You know where the toughest guys hang out. Round ’em up — get a gang together. I need a dozen anyway, and when I say tough, I mean tough. See that every man jack of ’em is heeled — an’ see that he knows how to shoot.”

“You ain’t never done this sort of thing before, boss,” said the voice of an assistant complainingly. “You’ll get mixed up with the law.”

Banton’s answer was a fierce snarl. “Maybe I ain’t never had good reason to. The law won’t know anything about it.”

Instructions followed, instructions to which Agent “X” listened closely. Banton was ordering his own men to round up a dozen of the fiercest gunmen and killers they could find. He was stepping out of his role of licensed private detective. He was ready to hurl defiance into the law’s face.

But Banton wasn’t telling his men what his secret purpose was. He was leaving them in the dark. He spoke again arrogantly.

“There’s a guy named Becker and another named Garino who’d be good. The cops want them for kidnapping the commissioner a coupla days ago. They’re hiding out and I know where. The other guys with them that pulled that crazy stunt skipped town. Get Becker and Garino.”

There was the whisper of money changing hands. Agent “X’s” eyes were bright, eager. “Slats” Becker and Tony Garino! Two of the very men he himself had hired. He, too, knew where they were hiding out. He had underworld contacts, systems of grapevine telegraphs. Now Banton was hiring them for some sinister purpose of his own. It opened another line of investigation for the Agent. Things were coming nearer and nearer a climax. The voice of Banton came through the amplifier again.

“Give ’em a hundred bucks apiece. Tell ’em there’s twenty times as much if they stick with me and use their rods right. And tell ’em to wait close. When things are ready I’ll give ’em the high sign.”

“When will that be, boss?”

“Tonight, maybe. Two of you guys come along with me. We’re going on a little trip. There’s more things I want to tell you.”

Agent “X” opened his door, stepped across the corridor, and retrieved his microphone. Tensely he coiled it up, then left the building.

He strode swiftly up the block, turned. He had left one of his cars parked beside the curb in front of an empty house.

Before entering it he retreated into the shadows, and his skillful fingers made quick changes in his face. He drew out the cheek plates that had given his features the sagging contours of middle age. He changed the hue of his complexion. He was no longer Andrew Balfour. He was younger, more dapper again. Banton would never recognize him as his fellow tenant in the bank building, and it was Banton Agent “X” was thinking of.

He got into his car, turned around, and waited close to the end of the block with the engine running, until he saw Banton and two of his aides emerge. They got into Banton’s flivver. The little car lurched off.

Agent “X” followed, and at the end of fifteen minutes he felt certain that he knew where Banton was going — so certain that he dared drop far behind. Banton was turning into a boulevard that led toward the suburbs, heading toward the distant yacht harbor that was a three-quarter-hour run from the city.

IN fifteen minutes more there was no doubt about it. Agent “X” loafed along behind. Single-handed, he was by degrees getting closer to the strange, sinister action that impended.

When they reached the town where the yacht harbor was located, Banton parked his flivver in the same side street. He led his two colleagues up on the hill.

Agent “X” instantly stopped his own car, climbed out, and cut through the darkness. The process of shadowing was easy for him now. He was crouched near the street that ascended the hill as Banton and his assistants passed. He followed them up the hill, and was near enough to see them standing on the bluff and hear Banton give low-voiced instructions. But what these instructions were Agent “X” missed. He saw Banton stride away, leaving his two men there. The agency detective walked into the little town, turned down an alley, and prowled along the shore.

Agent “X,” like a grim nemesis, followed. But Banton seemed to be on an aimless scouting expedition. On a clear patch of beach, where any moving figure was visible, Agent “X” had to let him get ahead.

Then suddenly Agent “X” stopped. Something black was heaving in the small turf that the harbor swells kicked up. It showed like a blotch, against the sand. It might be a box or a hat, but it stirred his interest.

He walked down the slope of the beach quickly, stopped. The thing was a box, but a leather-covered box — a camera.

It was no ordinary camera, either. The Agent saw that. He was a man experienced himself in all types of photographic equipment.

His fingers tightened over the water-logged, leather-covered box that had apparently been flung carelessly into the harbor. He snapped open the front, saw the fine, elaborate shutter mechanism, the special, many-glassed lens.

He felt along the surface of the camera with hands that trembled slightly — felt until he came to a screw pivot, the head of which seemed to be missing. From an inner rear pocket he took out a tiny screw that he had picked up two nights before on the roof of the bank building. He tried it on the pivot post of the camera, found that it fitted. His eyes were pools of light.

This was Darlington’s sky camera, the one that had been hidden the night he had been thrown from the roof, murdered.

And, in a flash of deductive reasoning, Agent “X” understood why it was here. Darlington’s murderer had hidden it in the quickest and most convenient spot — the canvas pickup sack that he had that night been getting ready. It had been brought to this harbor, tossed into the water by the killers. It confirmed the Agent’s belief that they were close at hand.

He had forgotten Banton for the moment. The camera occupied his thoughts. But his reverie was interrupted by the soft crunch of sand. The Agent whirled, but not quickly enough.

With the suddenness of swooping shadows, two figures leaped at him out of the semidarkness. One was brandishing a blackjack.

Before he could duck, the blackjack struck him a blow on the side of the head, and it seemed that a thousand multi-colored stars and comets showered down upon him from the black depths of the sky.

Chapter XVIII

IN that first instant of agony he fought against the sense of dizziness and pain that possessed him. He let himself collapse, deliberately, then twisted sidewise with a swift, rolling motion. The second blow of the blackjack missed him.

His hand flashed out with the speed of a striking snake, gripped the man’s wrist. The man let out a smothered, harsh cry. His companion fell on top of Agent “X.” Together they pressed him to the cold, wet sand, while the man with the blackjack tried to free his wrist and swing a death-dealing blow.

Agent “X,” interpreter of men’s motives, read murder in the silent, tigerish attack of these two. They had come upon him looking at the camera, caught him prowling, snooping. He was to be destroyed as a menace to some criminal plot.

Sensing his closeness to death, Agent “X” summoned his keenest faculties, mental and physical. The man’s blackjack might not be the only weapon.

With his free hand, Agent “X” struck a crashing blow at the nearest man’s face. He couldn’t see any features. There was only a black head outlined against the faint grayness of the sky.

The man grunted, relaxed his clutch. Agent “X” twisted again with a motion like a steel spring released. His fingers still gripped the wrist of the blackjack holder. The man cursed, relaxed his clutch on the weapon. Agent “X” broke free, leaped to his feet and kicked the blackjack toward the water.

Both men rushed him, tried to force him toward the surf. The clenched fist of one caught him in the jaw, snapping his head back. He struck out again, and knocked one of the men in the sand; then he leaped away and ran in a zigzag course up the beach. As he did so there was the thudding report of a silenced gun and a bullet screamed close to his head. The next moment he was in the black shadows under the broken piles of an old pier.

The two men ran up the beach and stood in the shadows of a shed. He couldn’t see their faces. Their voices were two low for him to hear. It was only his phenomenally keen eyesight that made it possible for him to see their outlines at all.

At a fast stride they struck off along the beach, keeping close to the wharves and sheds, keeping away from the lighter sand. But the Agent followed as persistently as he had trailed Detective Banton. Perhaps, for all he could tell, one of them was Banton.

He held his breath a moment later. The two men leaped up on a wharf that ran out into the harbor. He heard the creak of boards faintly under their feet. He followed, creeping along the wharf, stopping often to get the men’s silhouettes against the faint grayness of the horizon.

A covered yacht, apparently out of commission and laid up for the season, was snugged fast to the side of this wharf. In an instant the two murderous figures blended with the darker shadow of this and disappeared.

Agent “X’s” pulses hammered. He believed he was close to the secret of the murderer’s hideout. But, when he approached the yacht in the darkness, he could see nothing except boarded doors and carefully closed canvas coverings. To flash a light would be suicide. He had a feeling that eyes were straining there in the darkness.

He thought of Banton. Was one of these men the agency detective, and if not, had Banton gone back to the city?

He left the wharf and went back into the town. It was now pitch dark. But he located Detective Banton’s flivver, just backing out of the side street. Banton at the wheel.

Agent “X’s” face furrowed. If the yacht he had seen was the hiding-place of stolen loot there must be other accomplices in the city, and he didn’t want to strike till he could bring about the round-up of the whole murderous gang. If one or more escaped, the death-torch terrors might continue. The inner hunch which had so often directed him along the right track urged him to stick to Banton’s trail.

He got into his own car and followed the detective back to town. But he was not even careful now to keep the red tail-light of Banton’s car in sight. A daring plan had suggested itself. Two men whose addresses he knew would be offered jobs as gunmen in the mysterious gang that Banton was about to assemble—“Slats” Becker and Tony Garino. Becker was almost a head shorter than the Agent, but Garino was approximately his size.

Back in town he drove swiftly to the neighborhood where Garino was lurking, hiding from the police after the kidnapping of the commissioner. Knowing the greediness of the man, Agent “X” felt certain that he would not turn down Banton’s offer.

The place where Garino stayed like a wolf in hiding was a shabby rooming house in a tough neighborhood, a rooming house kept by a woman who specialized in the harboring of criminals.

The location of every room was familiar to Agent “X.” It was here that he had come to get in touch with Tony Garino, Monk Magurren, and the others in the first place.

He parked his car and moved forward confidently now. Diving through an alley, he crossed several cluttered back yards by the simple expedient of vaulting over their fences. He counted the fences, came at last to a yard where he stayed.

There was a light in the basement of the house. A witchlike old woman was puttering around in a dirty kitchen. But it was a room in the third floor that held the eye of Agent “X.” A light burned in this. There was a crack beneath the shade. It was the room where Tony Garino dwelt.

With the silence and agility of an ape, Agent “X” crept forward and drew himself up to the first platform of the rusty fire escape that snaked down the rear of the house. He ascended cautiously, testing each rung of the iron ladder to be sure that no squeaking bar betrayed him.

Just under the window of the third floor he paused. Raising his head he looked inside. He had come in good time.

Tony Garino, the white-faced black-haired gangster, was in earnest confab with one of Detective Banton’s men. They were just finishing their deal apparently. A hundred-dollar bill changed hands. Banton’s man handed the gangster a slip of paper. Garino talked with much gesticulating of his hands.

Ten minutes passed during which the Agent got hints through a lot of vivid pantomime. Then Banton’s man left. The actions of Garino showed that he was getting ready to leave at once, too.

He went to a shabby bureau, took a big automatic from a drawer, examined the clip, and shoved the gun into his coat. He knelt before the rusty gas stove that heated the room, turned it out, and, after it had cooled a moment, ran his fingers over the blackened burner. With the soot he had collected he made smudges on his face.

This clumsy attempt of Garino’s at disguise brought a sardonic gleam to the Agent’s eyes. The gangster was trying to guard against recognition by the police. But, to the Man of a Thousand Faces, it seemed rather ridiculous.

THE Secret Agent descended the fire escape as silently as he had come up it, crossed fences, and turned into the street. Garino was just coming out the door of the rooming house as he did so. He set off at a brisk pace up the street keeping well into the shadows.

Agent “X” followed, ducked through a side street, skirted ahead of Garino, and waited beside a porch stoop, as silent as the night itself. In the Agent’s hand now was the small, gleaming cylinder of a hypodermic needle. The reservoir of the instrument contained a highly concentrated, liquid anesthetizing narcotic of his own mixing.

Tony Garino never knew what had happened to him. The arm that flashed out of the shadows, the point of the needle that pierced his skin, were synchronized like an act in some well-rehearsed play.

Garino was drawn into the shadows and deposited with his back against the stoop just as the drug in his veins began to thrust him down into the depths of unconsciousness.

Leaving him there, Agent “X,” as though nothing had happened, came out of the street and walked swiftly to the spot where he had parked his car. He drove ahead to a point opposite the place where he had left Garino and stopped close to the curb.

A moment he scanned the street in both directions. A single pedestrian was hurrying along.

Agent “X” got out, raised the hood of his motor, and pretended to be absorbed in engine trouble until the pedestrian passed.

Then he closed the engine hood and raised the cover of the car’s rumble seat. He turned, darted into the shadows. When he came out he was carrying a limp burden — the inert body of the gangster.

The Agent now drove to one of his most accessible hideouts. Each was chosen with great care to give as much privacy as possible in regard to entrances and exits. This was a deserted house, like the one he had used when he had disguised himself as Police Commissioner Foster. He had possessed himself of it without asking anyone’s leave.

He carried Tony Garino into it, deposited the gangster in a ventilated closet, locked the door, and changed to the disguise of Andrew Balfour.

By kidnapping Garino he had gained for himself a method of entering Banton’s mysterious gang. In Garino’s pocket he had found the slip of paper that Banton’s man had given the gangster, telling where the gang was to be assembled. It was a water-front address. Time was precious. Garino was due there any time. But first Agent “X” wanted to find out what Banton was doing. Was he still in his office?

Completing the disguise of Andrew Balfour, he went out into the street again. He drove to the vicinity of the bank, parked his roadster, and strode forward, headed for the side entrance that he and Banton usually used. Then he paused, prickles of horror traversing his spine. A man staggered past the corner of the building into range of the Secret Agent’s vision. He wore the light-blue uniform of a special bank guard.

A light was playing in the air behind him, a wavering spectral light, like a pursuing will-o’-the-wisp. It became a jet of hissing flame that descended on the guard’s back and sent him writhing to the pavement where he lay, a charred and inert heap.

With a hoarse cry on his lips Secret Agent “X” leaped forward. He dashed around the corner of the bank building, risking the flaming death himself, and a scene of terror and disaster met his eyes.

The flaming torch bandits had returned. The Merchants’ and Manufacturers’ Bank had been raided, and the goggled, helmeted figures were escaping in their long, low roadster after a grisly carnival of robbery and death.

Chapter XIX

IT was a second before Secret Agent “X” understood the full horror of what had happened.

The front doors of the bank were open. Every window was smashed. Special detectives, driven back by the raiders, began running forward again as the murderers’ roadster shot away. But the terrible work had been done thoroughly.

A bank guard, shouting like a madman, was dashing toward the doors.

“They’re in there,” he screamed. “Marsh and von Blund! They must have got it, too! Those devils burned them like they did the others.”

The man’s face was twitching. His eyes were red-rimmed, staring. Other guards and detectives came slinking out of the shadows across the street, trembling, sheepish.

Agent “X” saw another blackened corpse lying up the block. A big guard, his face dripping with sweat, spoke hoarsely, close to the Agent’s ear, as though answering an unspoken accusation.

“We couldn’t help it — we had to scram. They drove us off with that flame gun of theirs. That poor fella tried to stick — and look what they did to him!”

Discipline had broken down. The demoralizing force of fear lay upon the survivors of the raid. Inside the bank, the icy hand of terror had fallen like a blight. Agent “X” entered with the first group of detectives. He heard the cursing cry of one of them.

“Look — they got them!”

The man was pointing through the open door of the bank’s business office. A sprawled, unsightly figure lay just inside the threshold. Beyond, close to a big desk, was another.

A detective bent down, fumbled with trembling fingers, and lifted the heat-corroded wreck of what had once been a handsome gold watch. Its crystal had melted under the blast of the death-torch, making the figures on its face as unrecognizable as the grisly horror from which the detective had taken it. But the monogram on its back was still visible: “F.M.”

“It’s him — Francis Marsh,” said the detective in an awed voice. “The killers got them both. That other’s von Blund.”

So thoroughly had the terrible death-torch done its work, that the blackened pieces of jewelry were the only means of identification. But they established the grim fact that the partners who had survived the first unsuccessful raid had met death in this second one.

“The safe was blown wide open,” said another detective. “They used enough nitro to sink a battleship. You could hear it ten blocks away.”

Agent “X” saw that the great vault of the bank had been cleaned out. Its door had fallen outward, the quadruple hinges ripped, the lock bolts cracked as though they had been brittle clay. Every bit of the cash was gone.

“Marsh asked for a special guard tonight, too,” said one of the surviving guards brokenly. “A big lot of cash had come in. They were getting their books straightened.”

Inside the office, with the remains of the two bankers, was a third corpse, identified as the body of an elderly bookkeeper.

Police sirens sounded outside. Agent “X,” in the guise of Andrew Balfour, was there when Burks of the homicide squad arrived with a battery of detectives. The face of the homicide squad head was bleak. His voice was bitter.

“I warned them the killers would be back,” he said. “I warned them to keep away from here at night.”

THE Agent’s eyes held steely brightness. He stood, his body rigid, staring down at the ghastly remains of this biggest of raids. Then he turned and slipped quietly out. If he stayed, there would be questions. It was only because of the confusion, the demoralization of the police, that his presence hadn’t been noticed. As a tenant of the building, he might be held as a material witness. And he had other reasons for going.

The lightning of the death torch had struck twice in the same spot. The significance of this filled Agent “X” with grim purpose, spurred him on to action. It was as though Banton had had secret warning of what was to happen tonight. Where was Banton?

Swiftly and silently Agent “X” slipped away from the police, away from the excited, tense crowds that were coming, attracted by the explosion. He found his parked car, drove furiously back to the hideout where he had left Tony Garino.

The gangster was still unconscious, and, removing him from the closet where he was breathing in peaceful unawareness, Agent “X” studied the man’s features.

He studied them with the close, detailed intentness of an artist and craftsman, even opening the mobster’s thick lips and staring at his teeth.

Two gleaming gold bicuspids characterized Garino’s smile. The Agent had not forgotten these.

As he began his deft, ingenious impersonation of the unconscious gangster, working under the brilliant glow of his portable acetylene lamp in front of his triple mirrors, he imitated Garino’s mouth first of all.

This was a simple matter. He opened a box filled with shells of thin, resilient gold alloy, shells that corresponded to each of his teeth. He snapped two of these over his own bicuspids and flashed a gold-toothed smile at himself. Then he began the quick impersonation of Garino’s features. His own face changed like magic under the deft touch of his fingers. When the face was finished, when Tony Garino seemed to be sitting there before the mirror in that hidden room, he slipped a toupee over his own brown hair, and smoothed it down to shiny sleekness with Vaseline.

Then he undressed Garino and assembled the man’s clothing. Before putting it on he got out another suit of special, thin material and attached it with spring clamps to the lining of Garino’s coat. When he had put on the mobster’s flash suit, the other beneath it did not show. Its bulk seemed only the stockiness of the gangster. He pushed Garino back in the closet, locked the door, and filled his pockets with an assortment of the mysterious objects that he was in the habit of carrying.

Then he turned his collar up, pulled his hat down, and hurried to the street. The address on the slip of paper that Banton’s man had given Garino was within walking distance. It was in a westerly direction toward the river.

As Agent “X” approached it, moving at a fast walk, the neighborhood grew steadily worse. He was in a street of junk shops and dark, dilapidated warehouses, busy places in the daytime but dark and sombre now.

He came to the street that fronted the water, crossed it, and saw the oily gleam of the river ahead. He passed between two pier sheds, walked down a boarded alley, and came to the flat expanse of another smaller pier that was used as a base for tugs out of service.

A group of dark-clothed men stood whispering in the gloom at the end of this dock. He saw them before they did him, watched them a moment intently, then retraced his steps and ran quickly to the nearest cigar store where there was a telephone. Closeted in the booth he made a mysterious telephone call to Betty Dale, asking her to relay a message from him to police headquarters.

WHEN he returned to the dock the men were still there, and their low whispers hushed as he approached. He could see the stiffening, suspicious attitudes of their bodies,

He walked as he had often seen Garino walk — for his disguises went further than merely assuming the features of the man he impersonated. He made each disguise a study in muscular co-ordination as well. A voice that he had heard before spoke hoarsely out of the darkness.

“It’s that mug, Tony!”

The Agent, peering intently, saw the pale face and slumped body of “Slats” Becker. The little gangster grinned wryly.

“We thought yer’d got cold feet, Tony!”

Another voice cut in, thick with anger, the voice of Banton’s man who had made the arrangements with Garino.

“Where the hell you been? What’s the idea? Didn’t I tell you to come right away? We expect the boss any minute!”

Agent “X” shrugged in Garino’s characteristic gesture.

“Excusa me! Maybe I no come back. I hadda say gooda-by to the skirt.”

Harsh laughter echoed his remark. Banton’s man hissed for silence. Looking around at the men who stood on the dock, Agent “X” saw the toughest bunch of gorillas he had ever found collected in one spot. Banton’s assistants were bad enough, but they were the sneaky stool-pigeon type. The men they had assembled were cutthroats, gunmen, the city’s most dangerous riffraff — rats who could be lured out of hiding only by the smell of blood or the glint of gold — beasts who prowled in the night. The pockets of each bulged. They were armed to the teeth.

Suddenly, off across the black water, a light winked. Three times — a space of darkness — another flash.

“That’s the boss now,” said Banton’s right-hand man. “Come on, you mugs — get ready to go aboard.”

Out of the blackness that lay over the face of the water, something long and gray appeared. It nosed toward the dock, cutting the swells silently, showing no lights except that one signal which had been doused.

It came nearer, showed like some monster of the deep. It was a huge, gray-painted motor cruiser. Its rakish lines, the sharp swell of its bows, proclaimed it a former rumrunner; one of the fastest, most sinister-looking boats that Agent “X” had ever seen. How Banton had acquired it, what black history lay behind it, he didn’t know. But, on the forward deck, cradled under a canvas tarpaulin, he saw the ominous shape of a mounted machine gun. The boat slid into the dock noiselessly, and the Agent’s expert ear knew by the faint, rumbling purr of the motors amidships that this craft was superpowered.

It had been built to outdistance the fastest patrol boats of the coast guard fleet. It had the lines of a destroyer; it was a destroyer in the full sense of the term.

Awed by the impressive craft, the cutthroat crew that Banton’s men had assembled swarmed silently down to the deck. The harsh, lumpy face of Banton himself looked out of the pilot house window. He and a single engineer had brought the boat from its former berth.

“Keep your traps closed!” Banton warned. “Any mug who talks will get a crack over the head. This isn’t a picnic!”

As silently as she had come, the long narrow boat nosed away from the dock, nosed out into the river, and slipped like a gray wraith across the water. The engines, Agent “X” knew, were only at idling speed. Banton was careful not to leave a wake. Once a man from the deck of a passing tug hailed them, staring in surprise at this craft that showed no lights.

But Banton paid no attention. Two of his men on port and starboard sides were watching intently, alert, it seemed, for danger. But the boat slipped on unmolested, and the lights of the city fell away behind.

IT was only then that Banton opened the motors to their mid-speed, and the gray craft seemed to lift out of the water and shoot ahead on throbbing wings. A white, hissing wake trailed behind it.

Banton came down from the pilot house, turning the wheel over to his most trusted assistant. He went forward, peeled the canvas off the machine gun, fingered the synchronized mechanism. The black snout of the gun seemed to thrust ahead like a finger, warning of evil to come.

It was then that a shrill cry sounded somewhere amidships. Agent “X,” in the group around the gun, turned. Banton turned, too, a fierce oath escaping him. A slim figure came running along the throbbing deck of the boat. Two other figures followed.

Banton stood, legs wide apart, amazement written on his heavy features. Agent “X” saw a white, tense face; the curves of a lithe body. Rosa Carpita!

The dancer came up to the group around the gun, up to Banton.

“Call your gorillas off,” she said scornfully. “They’re chasing me.”

“You!” Banton hissed, amazement and anger in his voice. “How did you get here?”

“You wouldn’t tell me your plans so I followed you. I don’t trust you, Banton. I’m sorry I let you in on—”

“We found this skirt stowed on board,” said one of the men who had chased her, “She was hiding in a closet.”

The girl, Rosa Carpita, drew herself to her full height. Her black eyes were snapping fiercely. Her face, lovely before, was contorted into harsh lines.

“Don’t forget, Banton, that I am your client — and that I employed you!”

Banton’s little eyes were gleaming. He took a step forward.

“You’ve no business here,” he said. “You’ll hafta go ashore.”

“I won’t,” the girl said. “I demand to know what your plans are.”

Agent “X,” witnessing this strange drama, began to understand. Banton made a harsh gesture. He scowled at the men around him.

“Keep still,” he warned. “Don’t talk in front of these rats. Come to the cabin!”

He turned, lumbered off, and the girl followed. There was a mutter of low-voiced speculation behind him.

Agent “X” followed softly, but Banton and the dancer went down to the cabin amidships. The door was locked. There were curtains over the ports. He could see or hear nothing of the strange conference that the two were having. His eyes gleamed, however. His alert brain was at work. When Banton came back alone ten minutes later, he wasn’t surprised.

“What did you do with the skirt, boss?” asked one of Banton’s men.

Agent “X” heard the harsh answer.

“Locked her up like the cat she is.”

It was plain to the Agent that Banton was in some way double-crossing his client, Rosa Carpita. The girl had followed him, come on board to find out what was going on. All this was consistent with Banton’s character as the Agent had sized it up.

Banton went back to the pilot house. For nearly an hour the speed boat rocked in the swells, its engines muttering idly, while Banton swung it in slow circles.

Banton’s voice came down from the open window of the pilot house at last. He gave an order that his assailants understood. They walked among the men on deck, marshaling them like soldiers.

Agent “X” saw the gleam of hidden weapons being brought out. Four submachine guns were taken from a locker. One of Banton’s men manned the tripod gun up forward.

“All you mugs get ready,” Banton said.

Off on the night-darkened horizon, in the mouth of the harbor, Agent “X” saw a shape moving, a boat slipping out, showing no lights. His nerves tingled with excitement. It came toward them like a sea ghost.

For an instant, as it was silhouetted against a short light, he saw that canvas still mantled its deck, that it was the same covered yacht he had seen tied up. It passed them a half-mile away, slipped out to sea. And then he heard the engines of the speed boat beneath him throb into life. Its bow swung, it seemed to leap ahead across the dark waters. The chase of death had begun.

Chapter XX

LIKE a snarling gray wolf of the sea Banton’s speed boat lunged ahead. Its prow was the snout of a wolf worrying a bone in bared fangs. The wake it kicked up was the lashing plumed tail of a marauding sea beast.

And Banton, wide-legged in the pilot house, was the man-demon who urged the beast on to the kill.

A tenseness had crept over that murderous crew. Agent “X” saw clawlike hands fondling gun butts; he saw the blood lust in the rolling whites of eyes. He heard short, barking sentences hurled from beneath bared teeth. A huge wolf with a pack of lesser wolves! There was blood on the moon tonight.

He was glad that the girl was below decks, glad that she was to escape the horror that lay ahead. For the whole fantastic outline of the deathly enigma he had been fighting was beginning to take shape. His own pulses were racing. His eyes were points of shimmering light.

The sea itself was silent, seemingly deserted. It was the silence before a storm — the dreadful silence that bore in it the threat of doom.

The covered yacht ahead was speedy. But Banton’s gray speedboat was faster still.

The distance lessened minute by minute. The white ghostly canvas covering the yacht’s deck showed. Those on board, whoever they might be, were keeping up the farce that the vessel was empty. What would Banton’s method of attack be?

The answer came soon.

“Stand ready to give ’em hell!”

It was Banton’s voice calling down from the pilot house. Agent “X” caught a glimpse of the man’s red face. Banton’s eyes were gleaming slits of wolfish cruelty.

“Rake her from stem to stern,” he bawled. “Now!”

One of Banton’s men crouched behind the tripod-mounted machine gun, pressed the firing lever. The gun leaped on its fastenings. Bronze-jacketed bullets sped across the night-shrouded waters. The cartridge belt writhed like a gleaming snake uncoiling, spitting its venom. The man behind the butt had once handled a Tommy gun for a mob of rumrunners. His fingers were practiced. His aim was true.

The bullets were riddling the canvas covering in a death-dealing stream. If men were there they would meet their doom. But the covered yacht sped on. There was no sign of life on board, only that grim white wake.

Cursing, as though steeled to something expected which did not come, Banton ordered two of the submachine gunners to open fire. The deathly, bone-rattling tattoo of the Thompson guns joined the clatter of the heavy-caliber weapon up front. Their snouts sprayed lead on the craft ahead.

THEY were close astern of it now. Banton twisted the wheel. Like a huge gray wolf circling its prey, the speed boat heeled over and went around the larger yacht. It tore past the yacht’s side while Banton’s henchmen kept up their withering fire.

Behind the bows of the yacht, the pilot house showed. The leaden spray from the muzzles of the Tommy guns concentrated there. Glass smashed. Sheet metal crumpled. Boarding was ripped as with a thousand fangs. The yacht suddenly heeled over. Its white spray lessened. It lay wallowing in the trough of the seas like a still gray ghost.

There was something ominous about its stillness. No moving thing showed. Banton began to swear like a madman. He bellowed another abrupt order. A man dived into a locker of the ex-rumrunner. He reared up clutching two corrugated missiles — hand grenades, “pineapples.” These were Banton’s aces in the hole.

“Give ’em hell,” he said again, and the man with the grenades hurled one across the space that separated the two craft. With unerring aim it dropped on the yacht’s deck.

A blast of orange flame came. A roar sounded. Pieces of wood and strips of canvas rose into the air. The bomb left a gaping black hole in the yacht’s deck, but Agent “X” doubted that it had penetrated below decks.

The yacht seemed to wallow like a great, still beast, watching, crouching.

Banton circled her again, making the engines of the speedboat roar as though by this display of sheer speed and power he could cow those on board the yacht.

“Get the grappling hooks out,” he shouted.

From another locker, two-pronged hooks were brought with ropes attached — relics, too, of rumrunning days — relics that had been used by hijackers.

With a burst of speed Banton cut into the yacht’s stern again. This time he didn’t sheer off. He held the speedboat’s bow straight for the other craft, turned slightly and ran alongside, so close that the metal sides of the two vessels scraped. Then he reversed the engines, backed water in a smother of foaming spray.

“Fling ’em,” he snarled.

The grappling hooks dropped on the yacht’s decks, caught in scuppers, hatchways, and capstans. The ropes were made fast. Then a gangster shrieked a hoarse warning. Like rats, the men, ready to board the yacht, fell back.

For a point of brilliant flame stabbed out from the yacht’s superstructure. It was a hissing, scorching will-o’-the-wisp of fire, that dropped like a lightning bolt on the speed boat’s deck.

Where it fell, sizzling flame burst up. The deck boards smoldered, crackled, flamed. The gray enamel turned black. The frightened yells of men mingled with the hissing of the flames.

Banton alone seemed calm. He had snatched up a submachine gun himself. He sprayed lead at the spot where the flame came from. The jet of flame flickered, forked out. It touched the cruiser’s pilot house.

With a howl of fear Banton left his perch, clattered down the iron stairs into the boat’s interior. The wicked tongue of flame licked the pilot house. It heated the metal sheathing, turned varnished boards and framework into crackling embers. It reduced the pilot house into a smoking ruin.

Banton’s men had taken refuge in the offside of the cruiser. Here, protected by twenty feet of the boat’s cabin, they were safe. Banton appeared among them, sweat streaming from his face, his lips curled back from his teeth, his eyes the eyes of a devil. He still held the machine gun in stubby fingers.

“We’ll get ’em,” he said. “Stand ready to board her, you rats.”

He walked stiff-legged through the cabin, smashed a port, and thrust the muzzle of his machine gun through. As a police lieutenant he had had practice with Thompson guns. He was a dead shot.

His fingers tightened on the trigger of the Tommy gun again. Its muzzle bobbed and clattered.

There came a sudden scream from the spot on the yacht where the flamethrower had sprayed fiery death. The jet of flame lowered, went wild, hissed into the sea, sending up clouds of white steam.

In the light of it the men on the cruiser seemed like crouching demons. Banton, with his clattering submachine gun, was the high priest of hell.

Agent “X,” climbing up an iron ladder to the sleek cruiser’s top deck, saw a man pitch headlong from the bridge of the yacht. He saw the strange, horrible weapon in the man’s hand clatter down.

“I got him!” howled Banton exultantly. “Now, you rats, come on — we’ll board her.”

Like a pack of howling, bloodthirsty wolves the gunmen and murderers of Banton’s assembled gang followed their leader. Up over the sides of the yacht they swarmed, a living wave of death.

Chapter XXI

IN the mad tumult of the raid no one noticed the actions of Secret Agent “X,” the man they supposed was Tony Garino. He was on his hands and knees on the top of the cruiser’s cabin now. He was fastening two black cylinders to the gray-painted woodwork, thrusting them, into the hard pine boarding with needle-sharp spikes.

They pointed aloft like miniature gun muzzles, pointed toward the black night sky. He pulled a wire on the top of each, struck a hidden sparker, and, in the interior of the black cylinders, foot-length fuses sputtered and glowed.

Then he dropped back off the cabin roof, leaving the cylinders where they were, black, silent fingers lifting to the clouds.

He started for the deck of the yacht, then stopped. Banton and his gangsters had boarded her, but they had not won the battle.

Like a waiting, wounded beast, the yacht came to life again. One of the men on board had been killed, but others remained. A round porthole along the top deck snapped open. Another black snout projected.

Agent “X” saw the streak of light that hissed from it. He saw the light burst into flame, heard the gangsters howl with rage and fear. Like rats taking cover they fled to the yacht’s stern deck and crouched there behind metal life boats and capstans — behind any refuge they could find.

One, a burly gunman with the face of an ape, knelt behind a coil of rope, trying to level his Tommy gun. The man in the open porthole saw him. It was the gunman’s undoing and death.

The gushing flame from the hideous Flammenwerfer leaped across space to the coil of rope. The rope became a mass of seething flame. The man behind it, jumping to his feet, shrieking with fear, became a human torch. He stumbled across the deck, then dropped, an inert, horrible mass of smoking cloth and flesh. The flame played over him until he no longer resembled a man.

A gangster, losing his nerve, screaming with terror at what he had seen, jumped from his place of hiding and dived over the yacht’s rail. Banton cursed like a madman.

He was crouched behind a heavy capstan. The flaming torch killer sought him out. The Flammenwerfer splashed liquid flame on the rounded metal surface of the capstan. Flame hissed on both sides of Banton, hissed over his head. He crouched, cursing, palsied with fear, until one of his men turned a Tommy gun on the open port where the liquid death came from.

Then the head of the flame-thrower disappeared. The flaming jet dribbled off, ceased. The gangsters stole out of cover again. A man with a pineapple bomb hurled it, and the side of the superstructure where the flame-thrower had been became a twisted mass of iron.

Banton, jumping from behind his capstan, white and trembling snatched two of the hand bombs from his henchman’s fingers. He dropped his machine gun held the pineapples at his sides, and crept forward like an enraged gorilla.

But the jet of liquid flame appeared in another spot, farther astern, sending the gangsters running like scared rabbits. They fled along metal alleyways, fled beneath the canvas, while the flame sought to follow them, burning the canvas covering above their heads. Another went down, wrapped in flaming shrouds. But the rest reached the forward deck of the yacht.

Banton hurled his pineapples. They missed their mark, struck a lifeboat, bursting it apart like the pod of a pea. The other fell into the water, sending up a geyser of white spray. Then Banton cursed and leaped forward with a gloating light in his eyes.

A strange, squat weapon lay at his feet — a weapon with a blunt muzzle, a pressure tank behind it, another tank where concentrated, inflammable liquid was stored.

Agent “X,” on board the yacht now, saw Banton lift the thing up. Banton held one of the flame-throwers in his hands. He gave the curved lever that served as a trigger a tentative press. The thing spouted a clot of flame that hissed and splashed on the deck. The pressure tank roared like escaping steam.

“Come on,” bellowed Banton, “we got ’em now!”

As though in answer, a jet of liquid fire sprayed down from an open window. Banton leaped aside just in time. Where he had stood the deck boards seethed with flame.

Banton, crouching behind a steel stanchion, turned the muzzle of his own weapon upward. The jet of flame wavered, went true. The other flame-thrower ceased firing. The port where he had stood became a circle of hissing fire.

The fear-stricken gangsters took fresh courage. The staccato beat of the submachine guns sounded again. A gang of men, under the direction of Banton, who held his flame-thrower ready, began tearing at a battened-down hatchway. Others struck with axes on the steel doors of the nearest entrance.

A WINDOW smashed in. A gangster hurled a pineapple bomb into the gorgeously furnished interior of the yacht. The explosion lit up the inside of the boat so that its ports looked like the red eyes of a monster.

Then a man pointed.

“What the hell’s that!”

From close by in the darkness a sputtering crackle sounded. A gangster screamed in fear as something rushed upward as though an imprisoned ghost of the sea were escaping.

They could hear the thing screaming higher and higher up, into the dark sky. Then, far above their heads, almost in the clouds it seemed, the darkness was ripped apart. Balls of fire, brighter than the flame-throwers, made a dazzling glow over the whole face of the sea.

“A rocket!” gasped Banton. “It’s that girl — she’s sending ’em. She’s signaling.”

He started for the side of the cruiser, stopped. Another rocket went up. But it rose from the top of the cruiser’s cabin. It left a visible trail behind it. The girl was not there. No one was there. The coming of the rocket seemed uncanny. It howled upward like a banshee, burst at last into red balls of fire that the sea wind whipped into myriad sparks. The sparks fell seaward in a shower, dimmed, faded, went out.

“It’s some double-crosser,” hissed Banton. “We’ll get him later! Now—”

He turned his flame-thrower on again as a shadow moved behind another port. He squirted liquid death along the superstructure of the yacht, until an answering jet of flame sent him howling back.

Like a battle of demons in the mouth of hell the two Flammenwerfers competed with one another, while the gangsters cowered back. The hideous flaring glow of the gushing jets of flame lit up the whole deck of the yacht. Banton’s face was the face of a devil, a man driven on by hate and greed.

Agent “X” caught sight of a hideous goggled head. The men on the yacht were fighting to keep their ghastly secret intact — fighting to retain the mysterious cargo below decks. Agent “X” knew what that cargo was. He could guess the identity of these men who fought with liquid flame, these men who spread terror and death behind them, leaving a trail of charred and blackened corpses.

But Banton was hardly better. He drove the other away at last, silencing the hissing snout of the Flammenwerfer above him.

Agent “X” was watching the fight, seeming to take part in it. The automatic in his hands gave barking reports from time to time. His bullets clanged off the steel sides of the yacht’s superstructure. He hadn’t forgotten that he was Tony Garino, gangster. He gave the appearance of being one of the battlers. But he was watching, waiting, his eyes sweeping the dark waters.

BANTON’S men were swarming into the luxurious cabin now. One of the steel doors had given in, loosed on its hinges by a pineapple bomb. At the head of the stairs, leading down to the saloon below, a helmeted figure appeared. Then the worst carnage of the battle took place.

Three gangsters, murderous rats from the city’s water fronts, were caught off their guard. Agent “X,” looking through a window, saw what happened. The jet from the Flammenwerfer reached them as they made a rush for the stairs.

It struck the foremost of them in the chest, and the man’s body seemed to disintegrate before the seething gush of flame. He stumbled backwards, his features disappearing. The others went down, too, became huddled hulks of men. The cabin’s interior was filled with the sickening odor of scorched flesh.

Then a submachine gun chattered from one of the cabin’s rear windows. Its quick death leaped across space before the man with the flame-thrower could change the direction of his jet. He dropped his weapon, stood at the head of the stairs for a moment like some goggling, hideous apparition. Then with a cry he threw up his arms and fell backwards, riddled with bullets — dead.

Banton was almost master of the ship now. His big face was bloated, red, his eyes bloodshot. The fear and carnage around him seemed only to whet his appetite for the thing he sought. He ran across the cabin, callously leaping over the grotesquely slumped forms of what had been three of his men. He started to plunge down the stairway, a flame-thrower in his hand. Then he paused. A shout had come from outside. It was a cry of fright and warning.

Above the crackle of automatics, above the sharp tattoo of a Tommy gun still playing, came another sound. It was a sound that sent prickles of fear racing up Banton’s spine. It was the eerie, wailing note of a siren — a note that he had heard often before in his life. Words came to his lips.

“The cops!” he gasped.

The siren’s note was joined by another — a third and a fourth, Banton stood trembling, white as a sheet. The sirens outside seemed to be clamoring like dogs, like hounds on the hunt — the hounds of the law.

He staggered to a window, looked out. From all sides it seemed, across the face of the dark waters, searchlights were stabbing, converging on the two boats that rolled and wallowed side by side.

He heard the throb of powerful motors, heard sharp bows cutting the swells. A gray shape like a leaping hound cut through a searchlight’s beam. It was a slim, fast coast guard patrol boat, and its decks were black with armed men.

With a hoarse cry of fury and fear Banton fell back.

“We’re trapped,” he said, and the words came from his lips as though wrenched by the quivering hands of Greed.

Chapter XXII

THE gangsters were like stricken men in that first moment of confusion while sirens wailed and searchlights stabbed upon them. They stood stunned, dazed — jaws slack, eyes wide. Then they took refuge in the yacht’s cabin with Banton.

He began cursing at them, ordering them to fight, telling them they would be killed if they didn’t. He lashed them with his tongue, put fear into their hearts. They commenced snarling like cornered beasts, then they crouched and fired at the patrol boats. A screaming, clattering volley of machine-gun bullets answered their shots.

Banton was almost like a maniac now. He saw himself cheated of the thing he sought. He lifted the captured Flammenwerfer gun, thrust its snout through a window of the cabin and squirted liquid fire across the water. He was making a desperate attempt to keep the patrol boats at bay.

The jet of flame missed its mark. Its line of trajectory became an arc. It hissed into the water, sending up billows of steam. Just beyond it, circling like slim greyhounds, the patrol boats edged nearer. Banton raised the gun higher. His face was a living fury. He had double motives now. He had never forgotten that the law had humiliated him, forced him to resign. And, wolfishly, he was ready to murder in order to guard the thing he had fought to possess.

The jet of flame almost struck the gray prow of a coast guard patrol.

Then the man disguised as Tony Garino made a slight movement with his left hand. He was in the cabin of the cruiser, crouched behind its steel walls with the others. No one noticed the darting motion of his fingers. No one noticed either the small glass vial that flashed through the air and shattered with a barely audible tinkle against a metal table leg. The colorless liquid in it seeped out.

But invisible fumes filled the air. A gangster nearest the table felt them first. He began rubbing his eyes. Then he dropped his gun, put both hands to his face and staggered across the floor, seeking air. The fumes were growing sharper, more astringent. They were the smarting fumes of concentrated ammonia that got into the eyes and made them burn and water.

A cloud of fumes drifted around Banton’s head, sucked through the draft of the window. The flamethrower waved his stubby hands. He howled with rage, screamed an oath. The gray boats in the sea before him became confused shadows as tears blinded his eyes. He lost all sense of aim, sprayed flame on the deck of the yacht. Then with a cry he flung the terrible weapon from him and put his hands to his eyes.

The gangsters’ fire had fallen off. The cabin was becoming untenable as the fumes filled it and thickened. One by one the gangsters stumbled through the exits to the deck. Some still clutched their guns, firing fiercely, aimlessly. A volley of machine-gun bullets smashed into one and he collapsed into a thrashing heap, then lay still. Others dropped their guns and raised their hands above their heads in token of surrender. The gray patrol boats began to edge closer.

AMONG the larger coast guard craft was one harbor police patrol. It was far from its accustomed beat tonight, but strange things were in the wind. Two of the most important officials of the city police department were on this boat, the commissioner himself, and Inspector Burks of the homicide squad. The trails of murder know no boundaries, and, though this sea battle was far outside the police boat’s territory, both men were following a murder path. Tense, rigid, standing beside the rail, Inspector Burks spoke.

“I thought it was phony when that tip-off came. The skirt wouldn’t give her name. She hung up on me — but after the killing at the bank tonight I was ready to try anything.”

The tall commissioner was silent a moment, then he touched Burks’s arm.

“They’ve had enough! They’re quitting. They know when they’re licked.”

He was pointing to the yacht, from the cabin of which the gangsters were stumbling, lifting their arms. The police boat came nearer and Burks let out a harsh curse.

“That fat guy — it’s George Banton, chief. What the hell’s he doing out here? Maybe he sent up those rockets!”

Both men were puzzled. All that had happened tonight was puzzling to the law. The tip-off had come into headquarters in a girl’s voice, informing the police that the death-torch murderers were planning a sea getaway. It had sounded fantastic, but a half-dozen coast guard boats had responded. The mysterious message had told them to wait until rockets went up. Those rockets were mysterious, too. Who was responsible for them?

Burks, standing at the rail of the police boat with the commissioner at his side, was trying to dope it out — and wasn’t getting far.

As the gangsters stood in a huddled group, still blinded by the ammonia fumes, the coast guard boats and the police patrol closed in. Searchlights played on the two vessels that were locked with grappling hooks. The dead men on the decks, the havoc caused by the flame-thrower, showed how fierce the battle had been.

Agile coast guardsmen were the first to leap to the deck of the yacht.

INSPECTOR BURKS swore harshly again and stared in amazement, for Banton was fighting like an enraged beast. Blinking through watery eyes he tried to yank an automatic from his pocket and fire at the coast guardsmen.

A balled fist knocked him flat. If he had tipped off the police and sent up rockets for help what was the matter with him? Inspector Burks couldn’t figure it out.

He climbed to the deck of the yacht with Commissioner Foster at his side. The coast guard boats had pushed in, surrounding the two locked vessels. Their crews were swarming up from all sides. Six cops from the harbor patrol joined them.

Banton was yanked to his feet by the man who had knocked him down. The private detective stood blinking, sullen. Burks hurled a harsh question at him.

“What the hell’s going on here, you rat?”

“Find out for yourself!” yelled Banton.

“You sent up those rockets, didn’t you?”

“Rockets! Do you think I’d call any of you lily-livered cops in to help me! The girl did it — the little—”

“What girl?”

Banton shook his head and sneered into Burks’s face. But at that moment two coast guardsmen brought a kicking, struggling figure between them up from the cabin of Banton’s ex-rumrunner. It was Rosa Carpita, the Spanish dancer. She wasn’t speaking English now. She had lapsed, screaming, into her native tongue.

“We found her locked in a closet,” said one of the men. Sweat dripped from his face. He was panting. “She don’t like being rescued,” he said.

Burks, growing more perplexed, bawled a question.

“How in damnation could she send up rockets locked in a closet?”

But he didn’t question the girl at the moment. A more important matter claimed his attention. The tip-off had been that the band of death-torch murderers were escaping in a yacht with their fortune in loot. It was to see the murderers rounded up that Burks and Commissioner Foster had come out here.

There were pungent fumes of ammonia inside the cabin, keeping the coast guardsmen back. Here was another mystery. Who had thrown them? The murderers on board the yacht, Burks decided.

The fumes began to clear. The cops and coast guardsmen entered. They held machine guns, automatics and sawed-off shotguns ready. There must be life still on the yacht, more of the flame-throwers. They were taking no chances.

Three hideous hulks that had once been men were sprawled on the floor of the cabin. They went on to the head of the stairs, then shouted. At the bottom of the stairs lay another figure, helmeted and goggled. One of the torch murderers — dead. The mystery of their identity was at last to be disclosed to the police.

Inspector Burks was trembling with excitement. The police had had little part in catching this band of sinister raiders, but he was in at the finish. If there were any left alive they would have to stand trial for the murders they had committed in the city.

It was Burks himself, gun in hand, who saw a face ahead of him along a passageway of the yacht. His features grew white. He thought he was looking at a ghost. Then the face disappeared, a door slammed. From behind the door Inspector Burks heard a single pistol shot and the thud of a falling body.

He leaped forward, yanked open the door, and stood, gun in hand, staring down.

A tall man lay at his feet, a man with stern, aristocratic features, blue eyes and light hair. The blue eyes were blazing now. The features were setting into the immobility of death. There was a cruel sneer on the aristocratic mouth.

“Von Blund!” gasped Burks.

He leaned against the wall, rigid, dumfounded. The man who lay at his feet was supposed to be dead already, slain in the last raid on the Merchants’ and Manufacturers’ Bank, a charred and hideous corpse identified by his cuff links and jewelry. Understanding of this ghastly mystery began to filter into Inspector Burks’s mind. With a harsh oath he stumbled back along the passageway, stooped over the goggled and helmeted figure at the foot of the stairs.

While Commissioner Foster watched, he ripped off the helmet and goggles exposing the dead face beneath. It was the commissioner’s turn this time to gasp in surprise.

“It’s Francis Marsh, inspector! In God’s name, what does this mean? He was killed tonight — burned!”

“We thought he was!” barked Burks. “Von Blund’s in there, too. He shot himself when he saw he was trapped, when he saw the game was up!”

“You mean—”

“I mean that the cleverest bunch of thieves and murderers in the history of the city pulled the wool over our eyes, chief.”

“What about Osterhout, Davis and Honor — the partners killed in the first raid?”

THE answer to that question came before Burks could speak. Two coast guardsmen came into the cabin carrying a sprawled figure on a piece of canvas. He, too, was goggled, helmeted. But the helmet, ripped off, exposed the face of Eric Osterhout — von Blund’s wartime partner, the man whose supposedly charred corpse found in the Merchants’ and Manufacturers’ bank had shown the wings of a flyer. He, also, was dead, riddled by bullets from the guns of Banton’s raiding gangsters. And a group of cops herded a shaking, thin-faced man into the cabin following the corpse.

It was Honer — the fourth bank partner. He had little stomach for action, and they had found him hiding in a closet.

But he wouldn’t speak. His bloodless lips were locked tight.

It was the black-eyed girl, Rosa Carpita, taken from the closet on Banton’s cruiser, who answered vehemently when Burks asked a question.

“What about Davis?” the inspector said. “He must be around here, too.”

The girl, standing in the door of the cabin, stamped her foot.

“Fools!” she said. “Bunglers! He is not here. He was killed — murdered!”

“That’s what we thought about the others,” answered Burks.

“But he was murdered, I tell you. I know. He was the only honest one. He told me terrible things were going to happen. He suspected, but he was afraid to go to the police. They, the murderers, hated him after he had been approached and had refused to aid them. Their bank was going to pieces. They were desperate men. So they killed him — because he knew too much.”

“And you were sweet on him, weren’t you, girlie?”

Color flooded Rosa Carpita’s dark face.

“You are impertinent,” she said coldly. “I shall not answer that question.”

“Why didn’t you come to the police if you knew so much? Why did you wait to tip us off tonight?”

“Tip you off?” Rosa Carpita pouted in puzzlement. “I did not tip anyone off. You are talking crazy. I employed that big pig, Banton, to catch these men. I wanted to be revenged.”

Banton spoke then, sneering through clenched teeth.

“She wanted to get her paws on the reward money that was up for the killers’ capture. But she got cold feet and called on you cops at the last minute.”

“You liar! You double-crosser! I didn’t get cold feet! I didn’t call the cops! But I would have if I could — after you locked me up and threatened to kill me.”

She turned to Inspector Burks, flinging a volley of words at him.

“This man is a crook, not a detective. I hired him to help me catch those murderers. I showed him the place where they were hiding what they stole. Jerry — Mr. Davis — had whispered many things to me. He was a good man — I wanted to see him revenged — and there was big reward out for his murderers. This pig, Banton, is right. We were going to split it. But he found out that they had so much money on board their boat. He was like the greedy hog. He was going to steal it — what you call hijack it — and then put me out of the way — whoof — so I would never tell nothing.”

“Now I get you,” said Burks. “Up to your old tricks, eh, Banton? You’re hooked on a murder charge now. You and you’re little pals here have been killing guys tonight. They were murderers, but the law don’t even allow that.”

He turned to Rosa Carpita.

“You better come clean — all the way, sweetheart! You did tip us off tonight, didn’t you? You figured your big boy friend, Banton, was going to cross you?”

Rosa Carpita started to speak, then held her tongue for a moment. A crafty look came into her dark eyes.

“It is right,” she said haltingly. “I did what you call tip you off. I knew that the big brave cops would be more generous than this fat pig, Banton. I knew that the reward would be mine for catching these murderers.”

Banton exploded into a scornful abuse. His voice was a sneer.

“She’s lying,” he said. “She’s got a tongue like a corkscrew. I thought she’d done it, too, first off. But she was in the closet, you say. That’s where I put her, an’ she didn’t have a chance to send up any rockets. One of my own mugs must have done it because he loved me.”

Inspector Burks scratched his head. The whole thing was mystifying. It would take hours to unsnarl. Rosa Carpita had changed her story suddenly — changed it when she saw a chance of getting the reward money. Burks’s puzzled speculations were abruptly interrupted.

From somewhere below decks a thumping noise sounded. It increased in violence, became steady, monotonous.

Thump, thump, thump!

It sounded like spirit knocking; like some of the ghosts of the dead come back to haunt the ship. The cops and coast guardsmen stared at each other in startled wonder. Then Burks voiced a harsh question.

“What the hell’s that?”

Chapter XXIII

THE thumping continued, and Burks gathered his men and went with them to discover its cause. They followed a passageway that led from the stairs at the foot of the yacht’s saloon, and the thumping grew louder.

“It’s somebody pounding,” said Burks. “Some guy’s trying to signal us.”

They walked quietly, tracing the thumping at last to the metal door of a closet. The door was locked, apparently on the outside. The thumping was repeated as monotonously as before. Then a man’s hoarse voice spoke behind the door, faint, muffled.

“Help — let me out! Help!”

Two stout-muscled cops seized the knob of the door and succeeded in forcing the lock. The door opened. Behind it was one of the yacht’s storage closets, and there, standing against the wall, hands and feet bound, was a man. He was a tall man, white-haired, well dressed, distinguished-looking. His face was honest. He was obviously a prisoner.

“Thank heaven,” he groaned. “I thought they would murder me, too.”

Burks was aggressive at first. “Who are you?” he said.

Then his manner became more respectful. When the tall man’s hands were untied, he fumbled in his pocket, brought out a wallet, and drew forth a card. This he presented to Inspector Burks.

On it was the name: “Carleton Madder, State Bank Examiner.”

Madder drew credentials from his pocket, adding these to the card.

“They kidnapped me,” he said. “They wanted help in disposing of stolen bonds. Then they planned to murder me afterward. They locked me in the closet when the attack began.”

Madder’s manner and appearance carried conviction. His credentials were above reproach. Burks nodded and handed them back.

When Madder was brought to the cabin above, Honer, the only surviving banker, stared at him blankly, but, whatever his thoughts, he kept them to himself.

The police and coast guardsmen continued their search of the yacht. They found hundreds of thousands in stolen cash, securities, and jewels — the loot of the murder band. It was transferred to the police boat, kept under heavy guard, to be rushed back to city vaults for safe-keeping before being returned to its owners. Coast guard boats attached hawsers to the two battle-ravaged vessels and made ready to tow them back to port. The death-torch killers would never rob or kill again.

Inspector Burks, Commissioner Foster, and the tall, dignified bank examiner named Madder, smoked in the cabin of the patrol boat as it sped away, its quest ended.

Inspector Burks voiced a question which seemed to be preying on his mind, and Madder, the bank examiner, hazarded an answer.

“I’m wondering about Spencer and Cox,” the inspector said. “Those were the two bank employees who were supposed to have made a get-away after the first raid. If they weren’t guilty what happened to them? Do you suppose—”

Madder, staring at the inspector, nodded.

“I suppose just what you do, inspector. They were the corpses found by the police alongside Davis’s body. The murderers had transferred their own watches and jewelry to their victim’s pockets to make it seem that they themselves were the ones who had died instead of the two employees whom they brutally murdered.”

“And the last two corpses — the ones we thought were von Blund and Marsh? Who could they be?”

THE tall bank examiner shrugged. “Underworld characters probably. The murderers must have had one or more criminal aides in such a well organized plot. We know now that they brought their loot directly to the bank in an ordinary armored car. Who were its drivers? I became suspicious myself when I saw the car come with a load which wasn’t accounted for on the books of the bank. I wasn’t satisfied with the explanation. They probably killed these criminal aides when they were of no further use and would only be in the way. Those were the corpses you found in place of von Blund and Marsh.”

Burks shook his head vigorously, offering an objection.

“What good would it have done, man, to take the cash to the bank vault? Answer me that?”

The tall bank examiner was leisurely in his reply. He lit a cigarette, blew smoke through his nose.

“It’s only a theory, of course,” he said. “But I overheard a few things. Osterhout and von Blund were former Prussian officers. One was a flyer. Both were men of action and daring. It is my belief that they transferred their loot to the roof of the bank building through a special shaftway leading from the vault. On the roof it was picked up by a plane and taken to the yacht.”

“Impossible! Fantastic!” said Burks.

“Perhaps — but I think subsequent investigation of the vault and the roof may prove that my theory is correct.”

Burks was still pondering this amazing explanation when the boat docked. The bank examiner was fidgeting to be off.

“I’ve a report to draw up and turn in,” he said. “You can call me later if you want me to testify.”

Unmolested, he leaped to the pier and strode away into the darkness, while the cops began to unload the loot to waiting armored cars summoned by radio.

For a moment Inspector Burks was preoccupied, then suddenly he stiffened and listened.

A faint whistle, eerie yet melodious, floated back across the dock. It seemed to fill the whole air, seemed to have a strange, ventriloquistic note like the call of some wild bird.

Inspector Burks’s eyes gleamed in quick understanding. He had heard that whistle before. He recognized it. It was the whistle of the “Man of a Thousand Faces,” the man whose identity was an eternal mystery.

A small boy came dashing through the police lines that cut off the end of the dock. A cop tried to stop him, but he ran on, clutching something in his hand. He sped up and thrust the thing in his hand under Inspector Burks’s nose.

“Here, mister,” he said. “A guy ast me to give it to you.”

It was a note, and in the boy’s pocket was a bright half dollar. His eyes were shining with the excitement of so much sudden wealth. Inspector Burks’s eyes shone, too.

The note was brief, explicit in some spots, mystifying in others.

“Darlington was murdered,” it said. “He did not commit suicide. Ask Rosa Carpita about the plane she hired under the name of Rollins, two nights ago. Ask her why she took the flight and what happened on it. And search the ventilators on top of the bank.” The inspector bent closer, staring intently. A faint “X” was visible at the bottom of the note — its only signature.

But the “X” and the writing above it, like the strange whistle sounding through the night streets, grew steadily fainter as Burks watched, and finally faded away, leaving only the blank paper in his trembling hand.