Fredericks was ready with the plug that extended, on the end of a short wire, from the metal model. Wilhelm was looking on.
The men did not notice what was happening behind them.
Scarcely had Biscayne and Cardona gone, before the door of Silas Harshaw’s bedroom had opened. Across the floor stalked a man clad in black — The Shadow!
As Fredericks finished screwing the plug into the baseboard, the three men watched the apparatus with interest. Nothing occurred, apparently. Then there was a click at the other side of the room.
The lights went out. The glare of a flashlight revealed the three men by the wall.
Staring into the bright illumination, they could see a hand in front — a hand that held a leveled automatic.
The light swung across the room. The startled men were afraid to move. The burning glare was upon them. The gun, threatening, seemed to force them backward.
“Move,” came a low, sinister voice. “Move back. Keep moving.”
With hands upraised, the three men backed away from the gun, forced to the door of the little bedroom. They did not know who this mysterious intruder menacing them could be. Only the hand of The Shadow was visible in that light.
The three were forced into the little room. The light clicked out; the door was drawn shut by an unseen hand. The key turned in the lock.
A soft laugh rippled through the study, where The Shadow was alone.
On came the lights of the room. Beside the door, The Shadow stood and watched the metal box that lay upon the floor beside the wall.
Deliberately, he opened the door to the outer room and stood there, waiting. There was no noise from the bedroom.
Weston and his companions were not yet bold enough to give the alarm.
The Shadow was expecting something. The innocent-looking object on the floor boded no evil; yet toward it, his gaze was focused.
But for his arrival and subsequent action, three other men would be watching here now — watching idly while they waited the return of Biscayne and Cardona.
The box clicked. Its top sprang apart. From its interior emerged a greenish shape that spread in all directions.
Swirling, sweeping, a vast cloud of deadly gas spread through the room!
The Shadow had expected this. He slipped into the outer room, closing the door behind him.
The spreading gas seemed to batter at the barrier, like a ghoulish, living creature thwarted of its prey.
No living person could have survived that killing vapor.
Three men had been doomed by this, the last of the insidious traps that had been made for murder.
They had been saved, by the intervention of The Shadow!
The window by the grating was open. The fumes thinned; then whirled in the direction of the opening. Sucked by the cool air outside, the deadly gas was gradually drawn from the room.
A stifling odor still persisted, but the menace of death had passed.
Commissioner Weston and his companions were pounding madly at the door of the little room.
They had smelled the pungent odor that had trickled from the study into the bedroom. They had sensed the cause, and had flung wide the windows to protect themselves.
With fresh air close by in emergency, they were trying to break down the barrier that restrained them.
No one heeded their cries.
Detective Cardona and Professor Biscayne were in the most distant part of the apartment. With two thick doors between, the shouts could not be heard.
They were not even audible to The Shadow, who stood in the outer room. He, too, was far away.
He was standing by the open door of the laboratory. Peering from the gloom, his keen eyes were studying the men who were searching there.
The eyes of The Shadow gleamed.
For the brain behind them knew!
CHAPTER XXIII
MURDER WILL OUT
JOE CARDONA had found the drawer marked E. From it, he was drawing papers that appeared to be what Professor Biscayne wanted.
Just as Cardona was about to call to Biscayne, his eyes noted an envelope that was among the papers in his hand.
A surprised look appeared in the detective’s eyes as he saw the scrawled notation:
DETECTIVE CARDONA — IMPORTANT.
From where had this come? The room had been searched quite thoroughly, although nothing had been removed.
Until now, the papers in drawer E had not seemed to possess importance. They had been regarded merely as rough, unfinished diagrams. But this envelope had not been seen.
It must have been placed here since the death of Silas Harshaw!
The word “important” prompted Cardona to action. Without calling to Biscayne, he tore open the envelope.
It contained a folded sheet of paper. Opening this, Cardona viewed a series of neatly inscribed words, that declared short, startling statements.
This is what Cardona saw:
Request Professor Roger Biscayne to telclass="underline"
(1) Why he has never stated that he knew everything that Silas Harshaw did.
(2) Why he has not stated that he is a member of the Merrimac Club and had a key to Louis Glenn’s room.
(3) Why he arranged the letter that told Thomas Sutton to look in the closet under the stairs.
(4) Why he risked the decision that asphyxiation was a sure death for James Throckmorton.
(5) Why he has not mentioned that he is the sole legatee in Arthur Wilhelm’s will.
Below was another series of closely formed tabulations:
Request Doctor George Fredericks to telclass="underline"
(1) Why he claims to have warned Harshaw of a serious illness that did not exist.
(2) Why he has said nothing about his knowledge of the deadly poisons that killed Louis Glenn.
(3) What he did with the check he received from Thomas Sutton, in return for two professional visits.
(4) What he did the night he was a guest of the Falcon Society, at James Throckmorton’s home.
(5) How much he expected to receive from Roger Biscayne in return for certain services.
These statements struck home as Cardona read them. The keen-eyed detective did not miss a single word.
His mind was now grasping the vital details of a vile plot — the schemings of two men who had laid their crimes upon the first man whom they conspired to murder!
Cardona looked at Biscayne, who was working at a spot in the far corner of the room. He looked at the list again.
Before his eyes, the writing was disappearing. A moment later, the paper was a blank! But those statements were still complete in Joe Cardona’s mind!
The detective slipped his hand into his coat pocket and gripped the butt of a revolver.
At that moment, Biscayne yanked at the side of a bench and pulled open a concealed drawer. He drew forth a small, round object, that appeared to be a miniature bomb.
“Look at this!” he exclaimed, turning toward Cardona. “Just by a chance, I discovered it. A small edition of the bomb that was sent to Arthur Wilhelm.
“By the way, did you find papers in the drawer where you were looking?”
“Stand where you are,” said Cardona coldly.
The detective knew now that he was dealing with a murderer. He wanted to ask questions at once; to confound Biscayne before he joined his confederate, Fredericks, in the other room.
“What is the matter?” questioned Biscayne, in a surprised tone.
“There are some things I want to know,” asserted Cardona with strange, slow emphasis. “Just how well did you know Silas Harshaw?”
“Only as an acquaintance—”
“Stop the bluff! I’ve got you, Biscayne. Got you with the goods!
“You were in back of this. All of it. I’m going to make you squeal, you rat! You killed Harshaw. You killed Glenn. You—”
Still holding the little bomb, Biscayne smiled and shrugged his shoulders. His eyes shone harmlessly.