A man crouched below the level of the staircase witnessed that swift getaway. The minute Dawson vanished, this man appeared lightly from the dimness of the stairwell. There was worry and concern on his watchful face. He knew that Kelsea had left the apartment some fifteen minutes earlier. He knew that Clyde Burke was in trouble of some sort, otherwise Clyde would have emerged from the apartment as soon as the gunman had entered the elevator.

The man in the hallway was Harry Vincent. Detailed to trail Kelsea, he had followed him to the hangout of Dawson - only to lose the slippery Kelsea a short time after the lawyer had left the apartment.

Vincent had retraced his steps instantly. The orders of The Shadow, relayed to him by the calm voice of Burbank, had been definite and explicit.

In case of an unforeseen upset he was to contact Clyde Burke and cooperate with him - and Vincent had recognized Clyde's voice talking to Dawson.

He got the apartment door open in a swift minute or so with a skeleton key. The moment he was inside he smelled the gas. A quick race to the kitchen, and he had the door open and was jerking Clyde Burke's head from the poisonous oven.

He closed all the gas c.o.c.ks and bent over the fallen man. Clyde's eyes were closed. His face was flushed, his breathing harsh and rattling.

Vincent was ripping the wadded newspapers from the jammed edges of the window when a voice behind him, with nasty distinctness, said: "Up with the hands, wise guy!"

It was Jimmy Dawson, motionless in the kitchen doorway. VINCENT shoved at the wall with his palm to give him the swift leverage for a plunging rush at his foe. But the hand of the crook moved with the swiftness of light. A knife in his hand whizzed with practiced skill across the room. It pierced the palm of Harry Vincent and pinned him to the wall.

As he tried to jerk the quivering steel free, he was met by a silent rush of Dawson. A blackjack struck Vincent on the jaw, tumbling him. Dawson was squatting on him like a vicious toad, smashing downward with the weighted weapon. Three times he struck. Then Vincent collapsed.

Clyde Burke lay on the kitchen floor, aware of what was happening but bound and helpless. He was still sick, nauseated. He knew Vincent and he were doubly doomed when he saw the gunman leap from the kitchen and return with a half-gallon jar of water in which a grayish, lumpy substance was suspended beneath the surface, Phosphorus!

"Yeah - phosphorus!" Dawson whispered, his voice thickish with haste and a cruel enjoyment. "This time, I'm improving on the stunt. I ain't takin' no chances. Figure it out for yourself, pal!"

From a cupboard he s.n.a.t.c.hed an empty lard tin. He poured water and phosphorus into the tin. In the bottom he punched a hole so that the water began to drip rhythmically. His finger swept across the front of the gas stove, turning on every one of the jets. Gas began to flood again into the small room.

"When enough water drips, the phosphorus will be exposed to the air. When that happens - blooie! - it bursts into flame. I figure five minutes, pal.

There'll be a swell gas explosion that will blow out the side of this house - and blow you guys with it. There won't be enough of you left for anyone to identify. Nice?"

He backed toward the doorway.

"And you can tell that guy with you," he snarled, "that he didn't fool me a dime's worth! I saw him giving me the eye from the staircase when I started to breeze. I took the elevator - two floors down and then came right up again.

I figured I could take you both - and I did!"

THE door slammed and was locked from the outside. The drip-drip of the water from the tin that held the phosphorus filled the room. To Clyde Burke's bulging eyes, the can was emptying at an alarming rate of speed. His heart sank as he saw the jagged hole near the bottom.

In his mad haste to arrange the trap and get away, Dawson had punched too large an opening. The gray lump of the chemical was already barely covered by the protecting water. In two minutes, maybe less - Vincent was unconscious, unable to do a thing.

Clyde tried to roll over, to force his dizzy body to his trussed feet. He managed to pivot for an instant on wavering knees, then the swirl of gas in his panting lungs made everything go hazy. He felt the impact of his face against the floor and knew he had failed.

Beside him, Harry Vincent was as quiet as a log; out cold.

JIMMY DAWSON wasted no time getting to the front room. He ran to the window of the living room. Too dangerous to sneak out through the building itself. Might be more of these d.a.m.ned private d.i.c.ks waiting below in the lobby.They'd get the building smack in their faces in about two minutes!

Dawson flung up the living room window and stepped to the fire escape. It was dark now outside, plenty dark enough to make a quick sneak without being seen. A cinch for a wise guy who knew just how to - The echo of a low-toned laugh made Dawson freeze where he was, with one hand still on the sill. His mouth gaped in terror as he saw a figure detach itself from the blackness of the brick wall. The figure uttered no sound except that ominous laugh. It was robed in black. A slouch hat covered all of the face except the jutting, beaklike nose and the deep-set flaming eyes.

"The Shadow!" Dawson gasped.

Gloved hands shot toward him, hurled him backward into the room. The Shadow followed like a streak of darkness. Dawson rebounded from the floor and darted for the apartment exit. The Shadow was clutching for him, his gloved fingers swooping without mercy, when suddenly the gesture stopped in mid-air.

The nose and the ears of The Shadow had transmitted a double warning to his brain. Gas - and the queer drip-drip of water!

He divined instantly what the combination of the two might mean. He whirled, raced along the narrow pa.s.sage that led to the kitchen. He knew that Dawson was already making his getaway. But he knew also that hundreds of innocent people were in peril of death from the blast of a planned gas explosion. He didn't hesitate in his choice.

A quick turn of the key in the kitchen lock and the door flew open. The Shadow saw the perforated lard tin. He s.n.a.t.c.hed it in the trembling second that the topmost tip of the phosphorus reached the surface of the fast-draining water. His left hand turned on the water faucet of the sink. His right lifted the can in one dexterous scoop and set it under the stream of cold water.

The room remained deadly quiet. Water ran over the edge of the overflowing can, drained down the sink with a faint gurgle. That was the only sound. The phosphorus was still a sodden gray lump under water. No flame leaped from it to ignite the gas-filled room.

By his quick, unhesitating choice The Shadow had averted an explosion that would have turned the whole building into roaring chaos.

THE SHADOW knelt above the helpless bodies of his two agents. He had already opened the window. Clean, fresh air gushed into the tiny kitchen.

The Shadow had received the report of the taxi driver, Moe Shrevnitz, relayed to him by Burbank. He had raced grimly to this apartment to trap Dawson and take him to a guarded spot for questioning. He had failed in this purpose.

But The Shadow was content. He was not a machine, but a living man.

Better a thousand Dawsons escape than a single innocent person be killed.

In quick, curt phrases he began to interrogate Clyde Burke concerning Alonzo Kelsea. His eyes glowed strangely when he heard the word "Foxhound."

CHAPTER VI.

THE RIDDLE OF COLETTE.

LAMONT CRANSTON sat in one of the deep leather chairs at the Cobalt Club, a newspaper lying idly on his lap. His eyes were half closed. In spite of the fact that it was early forenoon, there were half a dozen club members in thelounge, and Cranston didn't want to be drawn into aimless talk with them.

His mind was at a white heat of interest. The headlines of the newspaper in his lap confirmed in greater detail sensational news he had heard already from the lips of Police Commissioner Weston.

Cranston had called up Weston the evening before, had innocently led the talk to the subject of Leland Payne's death and the pier murders; and Weston, excited and jubilant, had given him a tip. The tip, just received from Washington, concerned the ident.i.ty of the mysterious "Herbert Baker," whose still unsolved murder aboard the Loire had plunged the city into its most baffling crime puzzle of a decade.

A headline, black and flaring, extended across the entire top of the newspaper on Cranston's lap: "BAKER" IDENTIFIED AS BACKUS,.

ESCAPED CONVICT; INVESTMENT.

TRUST CRASH REOPENED BY D. A.

Thomas Springer, Vanished Trust President, Suspected of Death of Former Subordinate.

Lamont Cranston a.s.sembled the facts in his mind. For the moment, he ignored the murder of Leland Payne. He concentrated on two men: Herbert Backus and Thomas Springer.

Between them they had thoroughly wrecked the Investment Trust Co., escaping with a cool twenty million dollars stolen from the pockets of ruined men and women all over the country. They had left a trail of suicide and disaster behind them. Springer was the rascally president, Backus the chief accountant.

Not a trace of Springer or the twenty million in loot was ever discovered.

Backus was caught, tried, convicted, sentenced to a term of forty years in jail.

In less than two years, he broke jail and escaped. His death on the Loire was the first news of his whereabouts since the night he had fled jail with the help of a guard he had bribed.

Cranston's lips curved in a grim smile. Unlike the police, he had never regarded Backus as anything more than a deluded tool of a cold-blooded and daring master crook. All through his trial, Backus had protested his innocence, steadfastly denied any knowledge of the stolen twenty million or the whereabouts of the vanished Thomas Springer.

Cranston believed him. But the evidence was so strongly woven about the unfortunate chief accountant that he was unable to clear himself.

And now - his cabin ripped to pieces in a hurried search; his body murdered by Jimmy Dawson, or someone who looked like Dawson - Backus had returned to the newspaper headlines for the last tragic time.

WHY had Backus escaped so daringly from jail, fled to Europe, returned under a forged pa.s.sport - and been murdered? Obviously because his intent had been to clear himself at the expense of the rascally Thomas Springer, who had vanished into thin air with every penny of the twenty millions of loot four years before.

If Backus had discovered proof of Springer's present ident.i.ty and whereabouts, he had been in an excellent spot to d.i.c.ker with the police for a pardon and the huge reward that had been offered by a committee of Investment Trust stockholders.

Dawson, or some other agent of Springer, had searched that cabin todestroy the evidence. The fact that the cabin was ripped to pieces and that Dawson was empty-handed when he had shot Pat Malone, the pier detective, was proof enough to Cranston that the murderer had been unsuccessful in finding that which he was seeking.

Backus was dead - but what had happened to the evidence gathered so desperately in Europe by a revengeful convict? Had it actually been hidden in the Loire's cabin? Cranston didn't believe so. Backus would have known the risk he was running and have prepared for that contingency. Where, then, could the evidence be for which Thomas Springer had already engineered cold-blooded murder? And under what name and what new ident.i.ty was the wily Springer now masquerading in New York?

That he was smart, cunning, completely secure in his new role, was evinced by the fact that not one penny of the twenty million he had stolen had ever been recovered. Evidently he had established credits in a dozen European banks under a dozen carefully built-up aliases. With such a fortune he could a.s.semble around him a gang of criminals to surpa.s.s any the baffled police had ever before been forced to cope with.

Lamont Cranston rose from his chair, took his hat and coat from an attendant and walked quietly toward the ornate exit of the Cobalt Club.

He climbed into the expensive roadster he always used when he drove himself. He had a definite goal in mind. He was driving to the pier of the America-Gaul Line. He knew that the Loire was now again in port. He wanted to ask a few innocent questions, and have a keen look at the cabin in which Backus had been murdered.

JOE CARDONA sat solidly in his chair at police headquarters, his dark, square-cut face thoughtful, worried. With him was Charles Malone, brother of the detective who had been shot down on the pier when he had tried to stop Dawson for questioning.

Malone's face was bitter, tragic. He had dropped in to find out if Cardona had any fresh news about the case.

"I've hired a private detective," he said. "You don't mind?"

"Not at all," Cardona snapped. "The more help we can get on this case, the better I'll like it." He smiled wanly, patted his visitor briefly on the shoulder. "I can well understand how you feel. Pat Malone was a fine police officer. He was killed like a rat because he stood in the way of something big in the crime world. Bigger than your brother, or Backus, or this acquitted gunman, Jimmy Dawson."

"You mean Springer, of course? The missing president of the Investment Trust Co.?"

"Yeah. I think that -"

The phone rang and Cardona scooped it from the desk with a quick gesture.

Charles Malone sat quietly, unmindful of the low voice of Cardona at the transmitter.

He sat there, bitter at the failure of the police, rubbing his iron-gray hair with a confused and angry gesture. He didn't notice that Cardona had finished his telephone talk until Joe caught him eagerly by the arm. He saw then that something unusual was in the wind. Joe's face was alert, his dark eyes shining.

"Come on!" he growled. "I've just had important news from the America-Gaul Line. Maybe we're getting our first real break in this case." "News?" Malone asked dully. "From whom?"

"The purser of the Loire. She's back in port today. The purser says he's found new evidence in the Backus killing. Something that seems to involve one of the cabin stewards."

Malone lost his hopeless look. He sprang to his feet. The two men hurried downstairs and caught a taxi at the curb. In twenty minutes they had pa.s.sed the guard at the pier end and were aboard the huge liner, conferring with a thin Frenchman in uniform, who was the ship's purser.

THERE were two other people in the room - a very frightened steward and an equally frightened stewardess. The man was tall, gaunt; the woman very fat, black-haired. She began at once to jabber excitedly in French at Cardona, until the purser halted her with a curt command.

"This is Colette Duval, stewardess on D Deck. The man is Pierre Renoir.

He had charge of the aft section of cabins on B Deck - where the man Backus was killed. Pierre, tell these gentlemen exactly what you told me."

The steward gave Cardona a sidelong, frightened look. He spoke slowly.

The purser translated, when he lapsed occasionally into French. He had, he admitted, been the first man to reach the cabin when Backus had screamed his death cry.

Backus was on the floor. Dying, not dead, as the steward had sworn at first.

Pierre had bent over him and the dying man had whispered something. A word, a name.

"Whose name?" Cardona rasped.

Pierre's troubled gaze moved to the fat stewardess. "He say: 'Colette,'

m'sieu'," he admitted in a low voice, to the frowning detective.

Cardona's face was grim. "Colette, eh?" He swung accusingly toward the woman. "Your name is Colette Duval?"

"Yes."

"You knew the pa.s.senger, Backus? You were in his cabin, perhaps?"

"No, no! I swear I know nothing of him, m'sieu'!"

"Then why did he whisper your name when he was dying?"

"I do not know."

"But you were up on B Deck - not down in D where you belonged!"

It was a guess, but it hit the mark.

The woman paled. "That is true. I was up on B."

"Why?"

"Because I - I wanted to meet Pierre Renoir. We are in love, m'sieu'. We hope to be married."

"Why didn't you report this matter at once to the police?" Cardona asked Pierre.

The steward shrugged. "It is murder," he whispered. "I know Colette cannot do this thing. But I am afraid to speak, until Colette at last advises me to tell truly what I heard. That I have done."

"Both these people are thoroughly reliable and honest," the purser interjected. "They have been with the line for years. To suspect either of murder, that is ridiculous."

"Yeah?" Cardona rapped. "I want to have another look at that cabin on B Deck. Upstairs, all of you."