He had dropped the telephone receiver without waiting to replace it on the hook and was now dashing madly out of the empty apartment and down the street.

The hall-boy at Warrington's had done exactly as I had ordered him. There was the elevator waiting as Garrick gave the five short rings at the nightbell and the outside door was unlocked. No one had yet discovered the fire which we knew was now raging on the top floor of the apartment.

We were whirled up there swiftly, just as we heard echoing through the hall and the elevator shaft from someone who had an apartment on the same floor the shrill cry of, "Fire, fire!"

Tenants all the way up were now beginning to throw open their doors and run breathlessly about in various states of undress. The elevator bell was jangling insistently.

In the face of the crisis the elevator boy looked at Garrick appealingly.

"Run your car up and down until all are out who want to go," ordered Garrick. "Only tell them all that an alarm has already been turned in and that there is no danger except to the suite that is on fire. You may leave us here."

We had reached the top floor and stepped out. I realised fully now what had happened. Either the robbers had found out only too quickly that they had been duped or else they had reasoned that the letter they sought had been hidden in a place in the apartment for which they had no time to hunt.

It had probably been the latter idea which they had had and, instead of hunting further, they had taken a quicker and more unscrupulous method than Garrick had imagined and had set the room on fire. Fortunately that had been promptly and faithfully reported to us over the optophone in time to localize the damage.

"At least we were able to turn in an alarm only a few seconds after they started the fire," panted Garrick, as he strained to burst in the door.

Together we managed to push it in, and rushed into the stifle of Warrington's suite. The whole thing was in flames and it was impossible for us to remain there longer than to take in the situation.

Accordingly we retreated slowly before the fierce blaze. One of the other tenants came running with a fire extinguisher in either hand from wall rack down the hall on this floor. As well try to drown a blast furnace. They made no impression whatever.

Personally I had expected nothing like this. I had been prepared up to the time the optophone reported the fire to dash over and fight it out at close quarters with two as desperate and resourceful men as underworld conditions in New York at that time had created. Instead we saw no one at all.

The robbers had evidently worked in seconds instead of minutes, realizing that they must take no risks in a showdown with Garrick. Rooms that might perhaps have given some clew of their presence, perhaps finger-prints which might have settled their identity at once, were now being destroyed. We had defeated them. We had the precious letter. But they had again slipped away.

Firemen were now arriving. A hose had been run up, and a solid stream of water was now hissing on the fire. Smoke and steam were everywhere as the men hacked and cut their way at the very heart of the hungry red monster.

"We are only in the way here, Tom," remarked Garrick, retreating finally. "Our friends must have entered and escaped by the roof. There is no other way."

He had dashed up ahead of the firemen. I followed. Sure enough, the door out on the roof had been broken into. A rope tied around a chimney showed how they had pulled themselves up and later let themselves down to the roof of the next apartment some fifteen feet lower. We could see an open door leading to the roof there, which must also have been broken open. That had evidently been the secret method of which the Chief had spoken to the Boss, whoever they might be, who bore these epithets.

Pursuit was useless, now. All was excitement. From the street we could hear the clang of engines and trucks arriving and taking their positions, almost as if the fire department had laid out the campaign beforehand for this very fire.

Anyone who had waited a moment or so in the other apartment down the street might have gone downstairs without attracting any attention. Then he might have disappeared in or mingled with the very crowd on the street which he had caused to gather. Late as it was, the crowd seemed to spring from nowhere, and to grow momentarily as it had done during the raid on the gambling joint. It was one of the many interesting night phenomena of New York.

What had been intended to be one of the worst fires and to injure a valuable property of the Warrington estate had, thanks to the prompt action of Garrick, been quickly turned into only a minor affair, at the worst. The fire had eaten its way into two other rooms of Warrington's own suite, but there it had been stopped. The building itself was nearly fireproof, and each suite was a unit so that, to all intents and purposes, it might burn out without injury to others.

Still, it was interesting to watch the skill and intuition of the smoke-eaters as they took in the situation and almost instantly seemed to be able to cope with it.

Sudden and well-planned though the incendiary assault had been, it was not many minutes before it was completely under control. Men in rubber coats and boots were soon tramping through the water-soaked rooms of Warrington. Windows were cracked open and the air in the rooms was clearing.

We followed in cautiously after one of the firemen. Everywhere was the penetrating smell of burnt wood and cloth. In the corner was the safe, still hot and steaming. It had stood the strain. But it showed marks of having been tampered with.

"Somebody used a 'can-opener' on it," commented Garrick, looking at it critically and then ruefully at the charred wreck of his optophone that had tumbled in the ashes of the pile of books under which it had been hidden, "Yes, that was the scheme they must have evolved after their midnight conference,—a robbery masked by a fire to cover the trail, and perhaps destroy it altogether."

"If we had only known that," I agreed, "we might have saved what little there was in that safe for Warrington. But I guess he didn't keep much there."

"No," answered Garrick, "I don't think he did. All I saw was some personal letters and a few things he apparently liked to have around here. I suppose all the really valuable stuff he has was in a safety-deposit vault somewhere. There was a packet of—it's gone! What do you think of that?" he exclaimed looking up from the safe to me in surprise.

"Packet of what?" I asked. "What is gone?"

"Why," replied Garrick, "I couldn't help noticing it when I opened the safe before, but Warrington had evidently saved every line and scrap of writing that Violet Winslow had ever given him and it was all in one of the compartments of the safe. The compartment is empty!"

Neither of us could say a word. What reason might there be why anyone should want Warrington's love letters? Was it to learn something that might be used to embarrass him? Might it be for the purpose of holding him up for money? Did the robber want them for himself or was he employed by another? These and a score of other questions flashed, unanswered, through my mind.

"I wonder who this fellow is that they call the Chief?" I ventured at last.

"I can't say—yet," admitted Garrick. "But he's the cleverest I have ever met. His pace is rapid, but I think we are getting up with it, at last. There's no use sticking around here any longer, though. The place for us, I think, is downtown, getting an earful at the other end of that detectaphone."

The engines and other apparatus were rolling away from the fire when we regained the street and things were settling themselves down to normal again.

We rode downtown on the subway, and I was surprised when Garrick, instead of going all the way down to the crosstown line that would take us to the Old Tavern, got off at Forty-second Street.

"What's the idea of this?" I asked.

"Do you think I'm going to travel around the city with that letter in my pocket?" he asked. "Not much, since they seem to set such a value on getting it back. Of course, they don't know that I have it. But they might suspect it. At any rate I'm not going to run any chances of losing it."

He had stopped at a well-known hotel where he knew the night clerk. There he made the letter into a little package, sealed it, and deposited it in the safe.

"Why do you leave it here?" I asked.

"If I go near the office, they might think I left it there, and I certainly won't leave it in my own apartment. They may or may not suspect that I have it. At any rate, I'd hate to risk meeting them down in their own region. But here we are not followed. I can leave it safely and to-morrow I'll get it and deposit it in a really safe place. Now, just to cover up my tracks, I'm going to call up Dillon, but I'm going up Broadway a bit before I do so, so that even he will not know I've been in this hotel. I think he ought to know what has happened to-day."

"What did he say?" I asked as Garrick rejoined me from the telephone booth, his face wearing a scowl of perplexity.

"Why, he knew about it already," replied Garrick. "I got him at his home. Herman, it seems, got back from some wild-goose chase over in New Jersey and saw the report in the records filed at police headquarters and telephoned him."

"Herman is one of the brightest detectives I ever met," I commented in disgust. "He always manages to get in just after everybody else. Has he any more news?"

"About the car?" asked Garrick absently. "Nothing except that he ran down the Pennsylvania report and found there was nothing in it. Now he says that he thinks the car may have returned to New York, perhaps by way of Staten Island, for he doubts whether it could have slipped in by New Jersey."

"Clever," I ejaculated. "I suppose that occurred to him as soon as he read about the fire. I have to hand it to him for being a deducer."

Garrick smiled.

"There's one thing, though, he does know," he added, "and that is the gossip of the underworld right here in New York."

"I should hope so," I replied. "That was his business to know. Why, has he found out anything really new?"

"Why—er—yes. Dillon tells me that it now appears that Forbes had been intimate with that Rena Taylor."

"Yes?" I repeated, not surprised.

"At least that's what Herman has told him."

"Well," I exclaimed in disgust, "Forbes is a fine one to run around with stool-pigeons and women of the Tenderloin, in addition to his other accomplishments, and then expect to associate with a girl like Violet Winslow."

"It is scandalous," he agreed. "Why, according to Dillon and Herman, she must have been getting a good deal of evidence through her intimacy with Forbes. They probably gambled together, drank together, and—-"

"Do you suppose Forbes ever found out that she was really using him?"

Garrick shook his head. "I can't say," he replied. "There isn't much value in this deductive, long distance detective work. You reason a thing out to your satisfaction and then one little fact knocks all your clever reasoning sky-high. The trouble here is that on this aspect of the case the truth seems to have been known by only two persons—and one of them is dead, while the other has disappeared."

"Strange what has become of Forbes," I ruminated.

"It is indeed," agreed Garrick. "But then he was such a night-hawk that anything might easily have happened and no one be the wiser. Since you saw him enter the gambling joint the night of the raid, I've been unable to get a line on him. He must have gone through the tunnel to the ladies' poolroom, but after he left that, presumably, I can't find a trace of him. Where he went no one seems to know. This bit of gossip that Herman has unearthed is the first thing I've heard of him, definitely, for two days."

"If Rena Taylor were alive," I speculated, "I don't think you'd have to look further for Forbes than to find her."

"But she isn't alive," concluded Garrick, "and there is nothing to show that there was anyone else at the poolroom for women who interested him—and—well, this isn't getting back to business."

He turned toward the street.

"Let's go down on a surface car," he said. "I think we ought to learn something down there at the Old Tavern, now. If these people have done nothing more, they'll think they have at least given an example of their resourcefulness and succeeded in throwing another scare into Warrington. But there's one thing I'd like to be able to tell Mr. Chief, however. He can't throw any scare into me, if that's his game."