BARTH nodded in agreement. The search began. The office was a simple task. Desk drawers revealed no traces of the lever, nor did the filing cabinet. Cardona lifted a covered typewriter from a small table, but did not find the lever beneath it.
Lessep was replacing his photographs in the filing cabinet when the others started out to search the laboratory. Only Darring remained, making a second search of the desk when the clang of a house-bell announced some one at the front door.
Wainwright Barth stood momentarily startled. He was in the center of the laboratory when he heard the sound. Then he saw Professor Lessep come trembling from the office. The old man’s face was pitiful.
“It’s Cranston,” reassured Barth. “Answer the door, professor. Warlock will go with you” — then, as Warlock hesitated — “and Cardona also. Come.” The bell tingled again. “Do not keep Cranston waiting.”
Barth led the way to the door and unbolted it. The professor went into the parlor. Cardona followed him promptly. Warlock hesitated; then remained. While he was standing beside Barth, Darring strolled up and joined them.
“It’s Cranston,” assured Barth.
Darring nodded. He stood beside the commissioner and waited, while Warlock nervously edged away.
A full minute elapsed. It was one of increasing tension. Then Barth, whose ruddy face had begun to show a strain, smiled weakly in relief.
The professor and Joe Cardona were returning. With them was Lamont Cranston. Sight of his friend’s calm face had eased the commissioner’s worry. For Wainwright Barth, unconsciously, had begun to feel the presence of an unseen killer.
His forced belief in an invisible menace had brought Barth to a state almost as fearful as that evidenced by Melrose Lessep and Findlay Warlock. The arrival of Lamont Cranston, through some singular reason, brought Barth a renewal of confidence.
CHAPTER VII. THE KILLER STRIKES
COMMISSIONER WAINWRIGHT BARTH became dramatic as soon as the three men had entered the laboratory. He closed the door and bolted it. Turning to Cranston, he beckoned. Then he led the way to the motor which Professor Lessep had attached to the glass cabinet.
“Strange things have occurred here, Cranston,” explained Barth. “An important connecting lever has been stolen from this motor. Apparently the theft took place after five o’clock this afternoon.”
The commissioner paused as he saw Cranston nod. The new arrival was examining the bolt from which the lever had been removed.
“Professor Lessep had a photograph of the complete motor,” resumed Barth. “If you wish to see it—”
“That is not necessary,” came Cranston’s quiet interruption. “I noted this motor very carefully last night. I recall the appearance of the part that is missing.”
Professor Lessep blinked as he heard this statement.
Silently, Cranston turned away and looked at the second motor. One by one, he picked up loose cords that were plugged to it.
“Some of these have been changed also,” he remarked. “See, professor? The ones with the special plugs are no longer here.”
“The special plugs?” inquired Lessep. “You must be mistaken, Mr. Cranston. There were no special plugs. Those are merely for making electrical connection. They have no other purpose.”
“Two of them were different from the others,” returned Cranston. “One which connected to the cabinet; the other to the floor socket.”
“I never knew it,” declared the professor. “All were standard cords and plugs. Of course, such items of electrical equipment differ in certain details.”
“These had unusually long contact points.” Cranston’s tone was methodical. “I noticed them, particularly, after they were detached last night.”
“But they are unimportant—”
“The professor is right,” put in Barth. “Perhaps some of these cords were moved about; but no important parts are missing, Cranston. What we must find is that lever. Aid the professor, gentlemen, while he resumes the search. I want Mr. Cranston to see the note that was left in the office.”
Lamont Cranston’s keen eyes watched the professor’s nod. Lessep started about the laboratory, with Cardona following him. Darring shrugged his shoulders; then joined in the search. Warlock appeared from the door of the little office. Seeing what the others were about, he entered into the hunt.
“Come into the office, Cranston,” suggested Barth. “I want you to see exactly where the note was found. Here — read it for yourself.”
They entered the office. Only the ceiling light was on. Barth approached the desk, clicked on the hanging lamp and pointed to the spot where the note had been.
Cranston nodded. He finished his examination of the note; then began to open the desk drawers.
“Nothing of importance in there,” said Barth. “Just carbon copies of letters — a box of electric light bulbs—”
He stopped as he saw Cranston pick out a yellow sheet of paper. It was a carbon copy of some letter sent by the professor. Barth watched Cranston compare the yellow sheet with the note that had come from the Unseen Killer.
“Agate type,” was Cranston’s comment. “Not well lined. An old-style machine, evidently purchased second hand at a bargain price. Odd, commissioner, how some of these letters correspond—”
Pausing abruptly, Cranston turned to the little table that bore the covered typewriter. He whisked away the cloth covering and smiled slightly, as he stooped forward. Then he motioned Barth toward the machine.
“Notice anything, commissioner?”
“Nothing in particular—”
“The ribbon?”
Barth adjusted his pince-nez.
“Ah, yes,” he said. “Two-colored — half red and half blue. Not uncommon for—”
He looked up to see Cranston’s smile; then noted the Killer’s message, that Cranston was holding toward him. The red signature, in its capital letters, was directly before the commissioner’s eyes. Barth uttered an exclamation.
“Examine the ribbon more closely,” came Cranston’s suggestion. “Particularly the red portion.”
Another exclamation from the commissioner. Barth, close to the typewriter, noted blue letter-marks — capitals — imprinted on the red half of the ribbon.
“What do those letters spell?” queried Cranston, still holding his thin smile.
“The Unseen Killer!” cried the commissioner.
“WHEN the red portion of the ribbon is seldom used,” reminded Cranston, “the keys invariably leave blue marks when they first strike it.”
The others had arrived. Barth’s shout had been heard in the lab. As they crowded up, four together, the commissioner turned and pointed to the typewriter.
“Mr. Cranston has made a discovery,” declared Barth. “The threatening letter was typed on your machine, professor. Here, in this office!”
Lessep shook. He bent forward as the commissioner pointed out the marks on the ribbon. For a moment, the professor seemed worried and speechless. Then, gathering himself together, he spoke.
“This proves that Crofton has been here,” declared the old man, solemnly. “Here, with his own unseen hands, he typed his warning. Even while we were first gathered in my laboratory, he could have prepared his terrible message.”
“Hardly,” came Cranston’s quiet objection.
“Why not?” queried Barth.
“The note,” explained Cranston, “was typed by some one who was alone in this office. Had any other person been present, the clicking of the keys would have been heard.”
“Correct,” agreed Barth. He made a calculation. “Then the message must have been typed between five o’clock and seven thirty, while the professor was out to dinner.”
“Only if the Unseen Killer typed it,” put in Darring.