With him were Commissioner Weston, Professor Biscayne, Doctor Fredericks, and Arthur Wilhelm. Detective Sergeant Mayhew was on duty outside the apartment.
“It looks foxy to me,” growled Cardona. “Briggs was mixed in it; but it’s so dumb it looks foxy.
“All the deaths before this were cleverly hidden. This one — straight to the source.”
“Don’t forget,” declared Biscayne, “that if the bomb had exploded, this would not have been so easily traced.
“If there had been a mysterious explosion at Arthur’s house, the chief evidence — the bomb itself — would have been destroyed.”
“The trail would have led here, anyhow,” persisted Cardona. “Packages would have been the first thing to ferret out and trace down. That bomb was charged heavily enough to blow up only one room — not an entire house.”
There was a long, deliberate pause. Roger Biscayne was thoughtful, considering deeply.
His eyes began to glow. His hand was moving up and down. He was preparing to speak. But Cardona anticipated him.
“We’ve got to hunt here,” said the ace detective. “This place is phony. That letter that was mailed here tonight—”
“Wait!” interrupted Biscayne. “It’s clearing in my mind! The final death — tonight. Why should the murderer worry about covering it up?
“His work was ended, by his own admission. The fifth death, and the last!”
“That doesn’t keep us from getting him,” responded Cardona. “A clever man would leave no clew.”
“These deaths were planned ahead,” declared Biscayne seriously. “This one was framed two weeks ago.
“The others — so far as we can ascertain — were prearranged. The murderer has had time to be far away—”
“Not far enough,” said Cardona grimly. “We’re going to get that guy, wherever he is! He won’t get away from us now. Not unless he’s dead, himself!”
The chance remark kindled a new burst of thought in Biscayne’s mind.
“Dead!” he echoed. “Dead! Suppose the murderer is dead! Cardona, you have struck it!”
“The solution?”
“Yes!” Biscayne was speaking emphatically, now. “Think of these crimes as one continued chain. Carefully planned, neatly executed — but inconsistent in one important point.”
“The notes,” remarked Cardona.
“Right!” resumed Biscayne. “Those death announcements, mysterious though they have been, were inconsistent. They could betray the man who sent them — unless he feared no betrayal.”
“I get you!” exclaimed Cardona. “If Homer Briggs thought he was going to be bumped off—”
“But I am not thinking of Homer Briggs,” interrupted Biscayne. “I am thinking of Silas Harshaw!”
“Silas Harshaw!” exclaimed Cardona.
All eyes were upon Professor Biscayne. His startling announcement was the most extraordinary idea that had yet been introduced into this case.
“I believe, now,” said Biscayne solemnly, “that Harshaw knew that he surely was going to die. He was the first to go.
“If any of the five marked men had known the truth, Harshaw would certainly have been the one.”
“HARSHAW was facing death,” declared Doctor Fredericks. “I told him so — when he asked me. He said he didn’t care. He had lived long.
“He talked about his inventions at the time; said his great work was completed. I recall some such talk — but the old man was always vague—”
“Facing death,” remarked Biscayne. “Death from failing health. It is always a terror to an active man, no matter how old he may be. I’m fathoming Harshaw’s thoughts, now.
“Perhaps he chose a quicker, surer death. He may have faced death that night, in this apartment. Faced it — knowing that his work was done—”
“He faced the window,” interposed Cardona, in a matter-of-fact tone. “He faced a shot through that grating.”
“Are you sure?” questioned Biscayne. “Come! Let us view that scene again. Let us reconstruct Harshaw’s death!”
The professor led the way to the study. He and Cardona stood beside the window. The detective, going back to his theory of death from without, crouched in front of the window sill.
He reached out and clutched the radiator. He drew himself upward.
Biscayne took Cardona’s place when the detective stepped aside. But as Biscayne duplicated Cardona’s action, he stopped suddenly and pressed his hand against the radiator.
“This radiator is cold,” he said. “That is strange. The one in the other room was sizzling.”
He turned the knob of the radiator and waited a few moments. There was no sound of entering steam.
Cardona stooped to the floor, and noted the radiator pipe. His examination was a close one.
“This isn’t connected,” the detective said. “It must have been out of order for a long time.
“There you are” — he pointed to the other end of the room — “there’s the gas heater the old man used. That’s why he had it — a bum radiator in this room.”
“Harshaw always kept the piece hot,” said Biscayne reminiscently. “Why should he have a faulty radiator here? The hotel would certainly have repaired it.
“He did not dislike steam heat. He used it in the other rooms—”
Biscayne broke off to watch Cardona. The detective was tapping along the radiator, examining it with his customary thorough method.
He had come to the center. There, between two sections, he was making a close inspection.
“Looks like a crack,” he said. “But it’s too straight to be a crack. Look at this thin line, professor. Does it mean anything?”
Biscayne saw what Cardona had indicated. The detective had his powerful flashlight directly against the center of the radiator.
The glare revealed a thin mark no wider than a penciled line.
“Something’s phony,” growled Cardona, trying to budge the sections of the radiator. “It’s a break all right, but something’s holding it. Give me a minute. I’ll figure it.”
Biscayne looked at the handle of the radiator. He turned it one direction, then the other. He pulled upward, but the knob did not move.
Then he twisted and pulled upward at the same time. The knob clicked slightly, and came up a full three inches.
“That got it!” cried Cardona. “The radiator splits! It’s coming apart!”
THE two sections of the radiator were opening toward the detective like the front of a cupboard. But before the detective had spread the segments more than a few inches, Biscayne sprang forward and thrust him aside.
Cardona, crouching, lost his balance, and tumbled ignominiously on the floor.
The sections of the radiator sprang back into place. The detective glared angrily.
Biscayne, anxious-eyed, was extending his hand to help Cardona to his feet.
The others, amazed, were awaiting the explanation of his action. It came.
“Sorry, old man,” said the professor. “It just occurred to me that you were taking a mighty grave chance.
“Harshaw was by this radiator; maybe he was opening it the way you were doing right now. And Harshaw was killed—”
The thought dawned on Cardona.
“Thanks!” he exclaimed. “Harshaw wasn’t the only one, professor. That other fellow — the yegg — Max Parker was—”
Nodding, Biscayne urged the other men to back away from the radiator.
He motioned to Cardona. He pointed to one side of the radiator.
“You take that half,” he suggested. “I’ll take the other. Pull together — and stay away from the front!
Cardona nodded. Together, he and Biscayne reached forward, one from each side of the radiator. They slowly drew the separate sections.
Cardona’s face was tense. Keen anticipation showed on Biscayne’s brow. Slowly, the radiator swung apart on hinges at the end.