Drew, however, was forced to wait seven minutes by his watch. He chafed at the delay. He crossed his legs at least once each leaden minute. He feared that the trail was getting cold. Twice he rose, as if to go.

Each time the secretary had indicated patience by an arching of her brows and a jerk of her thumb toward the ground-gla.s.s door.

"Send in Drew!" boomed as the door opened and let out the caller. Drew strode in with his notes in his hand.

"Just a minute, Westlake," he said, dropping into a chair and leaning over the desk behind which sat a good-natured official of the superior order. "A minute! I'm in a jam! What d'ye make of this?"

Drew related his discovery in the booths of the Grand Central. He went right to the point. He explained the auger-hole, the shavings, and the fact that it was the same set of booths to which the call had been sent from the prison, over the time Stockbridge had been slain.

Westlake listened with dawning light. He leaned back as Drew finished talking. He smiled. He thrust his thumbs under his vest. "You're a hardworking man, Drew," he said, "but you didn't get it all. Do you remember the third call that I gave you this morning?--the one when the chief-operator at Gramercy Hill put the howler on? It was from the same booths you just mentioned!"

"What?"

"It certainly was. There's no use looking at the record. The number was 9844 Gramercy Hill. In other words we have the evidence to show that a thin, whispering voice called up Stockbridge from one booth in the Grand Central at the same time the prison was connected to the adjacent booth."

"For the love of Mike!" said Drew.

"Yes--your case grows interesting, Chief. You've got a lot of tangled leads and all that, but a little more work should untangle them. A telephone engineer ought to make a crackerjack detective. He's trained to unsnarl the worst snarls in the world. You ought to see some of our wiring diagrams. It takes study to trace them out. You're learning!"

"I don't know if I am, Westlake. I think that Morphy, up at the prison, has been 'phoning New York. I believe he has a confederate in this town. This confederate, we will say, received his instructions about midnight last night. He bored a hole through the booths and called up Stockbridge. But what was it all for?"

"That I can't answer!"

Drew rose from the chair and crammed his notes in his inner, overcoat pocket. "What the devil did they do that for?" he asked with flashing eyes. "Morphy calls up Gramercy Hill 9843 at, or about, midnight.

Gramercy Hill 9844 calls up Stockbridge. Stockbridge was killed by a bullet in the neck as he's talking over the 'phone. Was the call to warn him? Was it to threaten him? Was it to occupy his attention so that the murderer could get in the room and fire the shot?"

"Did you find out how he got into the room?" asked Westlake, leaning forward.

"I have not! The whole thing gets weird. I can't sleep! I'm not going to sleep till I get some light on this!"

"You look healthy," said Westlake, as he pressed the buzzer for the next caller.

Drew emerged from the elevator and hurried to the street with short, quick strides. He crossed the snow and pressed open the door to a cigar store. He fished out a nickel and called up his office.

To Harrigan who answered, he said tersely, "Get Flynn up to the Grand Central! Get him to the east-end telephone-booth, on the lower level.

Tell him I'll be there. He's back from Morristown, isn't he? He phoned, eh? Get him to me! I need him!"

Drew hung up with a swift flip of the receiver. He hurried to the subway station and caught a local up-town. He had time to flash a fourth and fifth set of photos before Flynn came puffing across the lower level.

"See here!" snapped Drew, drawing the operative into the middle booth.

"Bend down there where that hole is, and tell me what you see on the varnish."

"It's fingerprints, Chief. Two, three of them. Looks like somebody pressed hard when they drilled that hole. The outer print is a good one of a thumb. Left thumb, I should say."

"That's right! I'm going to find out who made that impression, within one hour. You stay here and grab anybody who tries to talk with the prison. Frick is up there!"

"How about O'Toole, who's watching Nichols?" asked Flynn.

"Leave him stay on that a.s.signment. I need you here. Stick now! Watch everybody who talks over these three phones. Arrest anybody who receives or sends a call to the prison. There's plenty of Central Office men handy for a pinch. Fosd.i.c.k will back them up!"

Drew rushed for the subway. He realized that he had wasted valuable time by not taking the complete set of fingerprint photos on his first inspection of the booths. It was a detail he had overlooked. But then, he could afford to make mistakes. The men or man he was after, dared not make any. This was a thing he had often recalled in dealing with super-criminals.

Fosd.i.c.k's rooms at Detective Headquarters, on Center Street, were luckily deserted as he rushed down through the hallway. The Commissioner widened his eyes as Drew handed over the camera, with a request that the films be developed and prints made within twenty minutes.

"Can't be done that soon," said the detective. "Give us fifty minutes."

"I'll make it twenty-five!" shot Drew. "I got lots to tell you, but it'll keep. Get those prints and we'll land our man. The last two films have perfect samples of finger-work. Our man slipped there! He signed his own death warrant!"

The Commissioner pressed a b.u.t.ton. To the young man who came, he explained the necessity of rushing the developing and printing of the films. He turned as the messenger hurried out with the camera.

"What about that bullet?" he asked.

"Just as I said, Commissioner. It was fired from a smooth-bore pistol or gun. What do you think?"

"Oh, maybe not! Sometimes there isn't much rifling on an old revolver.

Those little twenty-two affairs are made out of cast-iron."

"But the cup.r.o.nickel bullet shows smokeless powder and high-cla.s.s criminal activity. I doubt if one of those little rods would take a modern steel-jacketed bullet. They're used in automatics."

"But automatics have good rifling. That bullet was as smooth as before it was shot. Here it is!"

Fosd.i.c.k opened a drawer and pulled out a later-day projectile of the lesser-caliber.

"This is smooth!" he repeated with heat. "It was cut from the old millionaire's brain. It ain't scratched. It never took the rifling it was intended for. My theory is, that it was fired from a gun of larger caliber. That is to say, it didn't fit the bore. A thirty-thirty rifle might be used to hold a twenty-two caliber bullet. It would not take the rifling of this."

Drew shook his head. "That's hardly possible," he declared. "It's too vague and doesn't suit me. We're going to find that the deeper we get in this thing, the simpler will be the explanation. I remember any number of cases which have been solved in this city where the mystery was so wrapped up in speculation and the improbable that our minds failed to grasp the simple thing which was the solution."

"Then you think the lack of rifling on the bullet might be the opening wedge to catching the man who shot Stockbridge?"

"It could well be, Fosd.i.c.k. The lack of a thing sometimes is just as important as the visible clue. Do you remember the Rajah case at Gramercy Park?"

Fosd.i.c.k leaned back in his chair and stared up at the ceiling. "Seems to me that I do," he said, thrusting out his lower lip. "There was a big jewel missing. Sort of an Idol's Eye case--wasn't it?"

"Exactly! A white diamond was missing at a dinner. Lights went out as they were pa.s.sing the stone around the table. Lights came on again and the diamond was gone. Everybody accused. A strange print was found on the sideboard. Servants knew nothing about it. The print didn't correspond to any which we took there. Seemed impossible and all that.

Well, the very fact that the print didn't correspond was the means of finding the stone and the culprit. You remember it?"

"Vaguely."

"Simple! A Lascar who waited on the table slipped off his shoes, crept into the room, secured the diamond and climbed to the sideboard where he hid it on top of a picture. The thumbprint which we puzzled our heads over was a toe-print! We got the fellow!"

"I recall it now," said Fosd.i.c.k. "I think one of our men thought out the matter."

"He didn't!" declared the detective. "We worked it out! The city department had given up the case. This may be the same. I'll venture to say that as soon as you get a good operative some private agency secures his services. Now, Commissioner, confess up. What manner of gun could fire a bullet, such as a cup.r.o.nickel one, without leaving markings?"

"Smooth bore. An old flint-lock--for instance."

"We'll grant that! They're clumsy, however. The shot which killed the millionaire was fired at very close range through a smooth tube of a greater caliber than the diameter of the bullet found in his head. If it were fired through a gun which was rifled, then there was a collar or collars on the bullet, which we didn't find. The same thing was discovered by examination of the sh.e.l.ls which the Germans fired at Paris. There was no rifling on those long-range projectiles. The bands dropped off after the sh.e.l.l left the gun."

"Then this bullet was fired at long range?" Fosd.i.c.k was openly incredulous.