"Well," he explained slowly as I opened my eyes wide in amazement at the minuteness of his researches, "those were the marks of the tire of an automobile that had been run up into the bushes from the road. You know every automobile tire leaves its own distinctive mark, its thumb print, as it were. When I have developed my films, you will see that the marks that have been left there are precisely like those left by the make of tires used on Warrington's car, according to the advertis.e.m.e.nt sent out by McBirney. Of course, that mere fact alone doesn't prove anything. Many cars may use that make of tires. Still, it is an interesting coincidence, and if the make had been different I should not feel half so encouraged about going ahead with this clew. We can't say anything definite, however, until I can compare the actual marks made by the tires on the stolen car with these marks which I have photographed and preserved."

If any one other than Garrick had conceived such a notion as the "thumb print" of an automobile tire, I might possibly have ventured to doubt it. As it was it gave food enough for thought to last the remainder of the journey back to town.

CHAPTER IV

THE LIQUID BULLET

On our return to the city, I was not surprised after our conversation over in New Jersey to find that Garrick had decided on visiting police headquarters. It was, of course, Commissioner Dillon, one of the deputies, whom he wanted to see. I had met Dillon myself some time before in connection with my study of the finger print system, and consequently needed no second introduction.

In his office on the second floor, the Commissioner greeted us cordially in his bluff and honest voice which both of us came to know and like so well later. Garrick had met him often and the cordiality of their relations was well testified to by Dillon's greeting.

"I thought you'd be here before long," he beamed on Garrick, as he led us into an inner sanctum. "Did you read in the papers this morning about that murder of a girl whose body was found up in New Jersey in the underbrush?"

"Not only that, but I've picked up a few things that your man overlooked," confided Garrick.

Dillon looked at him sharply for a moment. "Say," he said frankly, "that's one of the things I like about you, Garrick. You're on the job.

Also, you're on the square. You don't go gumshoeing it around behind a fellow's back, and talking the same way. You play fair. Now, look here.

Haven't I always played fair with you, Garrick?"

"Yes, Dillon," agreed Garrick, "you have always played fair. But what's the idea?"

"You came up here for information, didn't you?" persisted the commissioner.

Garrick nodded.

"Well do you know who that girl was who was murdered?" he asked leaning forward.

"No," admitted Garrick.

"Of course not," a.s.serted Dillon triumphantly. "We haven't given it out yet--and I don't know as we shall."

"No," pursued Garrick, "I don't know and I'll admit that I'd like to know. My position is, as it always has been, that we shouldn't work at cross purposes. I have drawn my own conclusions on the case and, to put it bluntly, it seemed to me clear that she was of the demi-monde."

"She was--in a sense," vouchsafed the commissioner. "Now," he added, leaning forward impressively, "I'm going to tell you something. That girl--was one of the best stool pigeons we have ever had."

Both Garrick and I were listening intently at, the surprising revelation of the commissioner. He was pacing up and down, now, evidently much excited.

"As for me," he continued, "I hate the stool pigeon method as much as anyone can. I don't like it. I don't relish the idea of being in partnership with crooks in any degree. I hate an informer who worms himself or herself into a person's friendship for the purpose of betraying it. But the system is here. I didn't start it and I can't change it. As long as it's here I must accept it and do business under it. And, that being the case, I can't afford to let matters like this killing pa.s.s without getting revenge, swift and sure. You understand?

Someone's going to suffer for the killing of that girl, not only because it was a brutal murder, but because the department has got to make an example or no one whom we employ is safe."

Dillon was shouldering his burly form up and down the office in his excitement. He paused in front of us, to proceed.

"I've got one of my best men on the case now--Inspector Herman. I'll introduce you to him, if he happens to be around. Herman's all right.

But here you come in, Garrick, and tell me you picked up something that my man missed up there in Jersey. I know it's the truth, too. I've worked with you and seen enough of you to know that you wouldn't say a thing like that as a bluff to me."

Dillon was evidently debating something in his mind.

"Herman'll have to stand it," he went on, half to himself. "I don't care whether he gets jealous or not."

He paused and looked Garrick squarely in the eye, as he led up to his proposal. "Garrick," he said slowly, "I'd like to have you take up the case for us, too. I've heard already that you are working on the automobile cases. You see, I have ways of getting information myself.

We're not so helpless as your friend McBirney, maybe, thinks."

He faced us and it was almost as if he read our minds.

"For instance," he proceeded, "it may interest you to know that we have just planned a new method to recover stolen automobiles and apprehend the thieves. A census of all cars in the questionable garages of the city has been taken, and each day every policeman is furnished with descriptions of cars stolen in the past twenty-four hours. The policeman then is supposed to inspect the garages in his district and if he finds a machine that shouldn't be there, according to the census, he sees to it that it isn't removed from the place until it is identified. The description of this Warrington car has gone out with extra special orders, and if it's in New York I think we'll find it."

"I think you'll find," remarked Garrick quietly, "that this machine of Warrington's isn't in the city, at all."

"I hardly think it is, myself," agreed Dillon. "Whoever it was who took it is probably posted about our new scheme. That's not the point I was driving at. You see, Garrick, our trails cross in these cases in a number of ways. Now, I have a little secret fund at my disposal. In so far as the affair involved the murder of that girl--and I'm convinced that it does--will you consider that you are working for the city, too?

The whole thing dovetails. You don't have to neglect one client to serve another. I'll do anything I can to help you with the auto cases.

In fact, you'll do better by both clients by joining the cases."

"Dillon," answered Garrick quickly, "you've always been on the level with me. I can trust you. Consider that it is a bargain. We'll work together. Now, who was the girl?"

"Her name was Rena Taylor," replied Dillon, apparently much gratified at the success of his proposal. "I had her at work getting evidence against a ladies' poolroom in Forty-seventh Street--an elusive place that we've never been able to 'get right.'"

Garrick shot a quick glance at me. Evidently we were on the right trail, anyhow.

"I don't know yet just what happened," continued Dillon, "but I do know that she had the goods on it. As nearly as I can find out, a stranger came to the place well introduced, a man, accompanied by a woman. They got into some of the games. The man seems to have excused himself.

Apparently he found Rena Taylor alone in a room in some part of the house. No one heard a pistol shot, but then I think they would lie about that, all right."

Dillon paused. "The strange thing is, however," he resumed, "that we haven't been able to find in the house a particle of evidence that a murder or violence of any kind has been done. One fact is established, though, incontrovertibly. Rena Taylor disappeared from that gambling house the same night and about the same time that Warrington's car disappeared. Then we find her dead over in New Jersey."

"And I find reports and traces that the car has been in the vicinity,"

added Garrick.

"You see," beamed Dillon, "that's how we work together. Say you MUST meet Herman."

He rang a bell and a blue-coated man opened the door. "Call Herman, Jim," he said, then, as the man disappeared, he went on to us, "I have given Herman carte-blanche instructions to conduct a thorough investigation. He has been getting the goods on another swell joint on the next street, in Forty-eighth, a joint that is just feeding on young millionaires in this town, and is or will be the cause of more crime and broken hearts if I don't land it and break it up than any such place has been for years." The door opened, and Dillon said, "Herman, shake hands with Mr. Garrick and Mr. Marshall."

The detective was a quiet, gentlemanly sort of fellow who looked rugged and strong, a fighter to be respected. In fact I would much rather have had a man like him with us than against us. I knew Garrick's aversion to the regular detective and was not surprised that he did not overwhelm Mr. Herman by the cordiality of his greeting. Garrick always played a lone hand, preferred it and had taken Dillon into his confidence only because of his official position and authority.

"These gentlemen are going to work independently on that Rena Taylor case," explained Dillon. "I want you to give Mr. Garrick every a.s.sistance, Herman."

Garrick nodded with a show of cordiality and Herman replied in about the same spirit. I could not fancy our getting very much a.s.sistance from the regular detective force, with the exception of Dillon. And I noticed, also, that Garrick was not volunteering any information except what was necessary in good faith. Already I began to wonder how this peculiar bargain would turn out.

"Just who and what was Rena Taylor?" asked Garrick finally.

Inspector Herman shot a covert glance at Dillon before replying and the commissioner hastened to rea.s.sure him, "I have told Mr. Garrick that she was one of our best stool pigeons and had been working on the gambling cases."

Like all detectives on a case, Herman was averse to parting with any information, and I felt that it was natural, for if he succeeded in working it out human nature was not such as to willingly share the glory.

"Oh," he replied airily, "she was a girl who had knocked about considerably in the Tenderloin. I don't know just what her story was, but I suppose there was some fellow who got her to come to New York and then left her in the lurch. She wasn't a New Yorker. She seems to have drifted from one thing to another--until finally in order to get money she came down and offered her services to the police, in this gambling war."