Again we saw the dim silhouette of a crouching man and the whisk of the small flame across the window as the signals were renewed. They came more rapidly than before – so rapid that it was hard to follow them.

"PERICOLO pericolo – eh, what's that, Watson? 'Danger,' isn't it? Yes, by Jove, it's a danger signal. There he goes again! PERI. Halloa, what on earth —"

The light had suddenly gone out, the glimmering square of window had disappeared, and the third floor formed a dark band round the lofty building, with its tiers of shining casements. That last warning cry had been suddenly cut short. How, and by whom? The same thought occurred on the instant to us both. Holmes sprang up from where he crouched by the window. "This is serious, Watson," he cried. "There is some devilry going forward! Why should such a message stop in such a way? I should put Scotland Yard in touch with this business – and yet, it is too pressing for us to leave."

"Shall I go for the police?"

"We must define the situation a little more clearly. It may bear some more innocent interpretation. Come. Watson, let us go across ourselves and see what we can make of it."

2

As we walked rapidly down Howe Street I glanced back at the building which we had left. There, dimly outlined at the top window, I could see the shadow of a head, a woman's head, gazing tensely, rigidly, out into the night, waiting with breathless suspense for the renewal of that interrupted message. At the doorway of the Howe Street flats a man, muffled in a cravat and greatcoat, was leaning against the railing. He started as the hall-light fell upon our faces.

"Holmes!" he cried.

"Why, Gregson!" said my companion as he shook hands with the Scotland Yard detective. "Journeys end with lovers' meetings. What brings you here?"

"The same reasons that bring you, I expect," said Gregson. "How you got on to it I can't imagine."

"Different threads, but leading up to the same tangle. I've been taking the signals."

"Signals?"

"Yes, from that window. They broke off in the middle. We came over to see the reason. But since it is safe in your hands I see no object in continuing the business."

"Wait a bit!" cried Gregson eagerly. "I'll do you this justice, Mr. Holmes, that I was never in a case yet that I didn't feel stronger for having you on my side. There's only the one exit to these flats, so we have him safe."

"Who is he?"

"Well, well, we score over you for once, Mr. Holmes. You must give us best this time." He struck his stick sharply upon the ground, on which a cabman, his whip in his hand, sauntered over from a four-wheeler which stood on the far side of the street. "May I introduce you to Mr. Sherlock Holmes?" he said to the cabman. "This is Mr. Leverton, of Pinkerton's American Agency."

"The hero of the Long Island cave mystery?" said Holmes. "Sir, I am pleased to meet you."

The American, a quiet, businesslike young man, with a clean– shaven, hatchet face, flushed up at the words of commendation. "I am on the trail of my life now, Mr. Holmes," said he. "If I can get Gorgiano —"

"What! Gorgiano of the Red Circle?"

"Oh, he has a European fame, has he? Well, we've learned all about him in America. We know he is at the bottom of fifty murders, and yet we have nothing positive we can take him on. I tracked him over from New York, and I've been close to him for a week in London, waiting some excuse to get my hand on his collar. Mr. Gregson and I ran him to ground in that big tenement house, and there's only the one door, so he can't slip us. There's three folk come out since he went in, but I'll swear he wasn't one of them."

"Mr. Holmes talks of signals," said Gregson. "I expect, as usual, he knows a good deal that we don't."

In a few clear words Holmes explained the situation as it had appeared to us.

The American struck his hands together with vexation.

"He's on to us!" he cried.

"Why do you think so?"

"Well, it figures out that way, does it not? Here he is, sending out messages to an accomplice – there are several of his gang in London. Then suddenly, just as by your own account he was telling them that there was danger, he broke short off. What could it mean except that from the window he had suddenly either caught sight of us in the street, or in some way come to understand how close the danger was, and that he must act right away if he was to avoid it? What do you suggest, Mr. Holmes?"

"That we go up at once and see for ourselves."

"But we have no warrant for his arrest."

"He is in unoccupied premises under suspicious circumstances," said Gregson. "That is good enough for the moment. When we have him by the heels we can see if New York can't help us to keep him. I'll take the responsibility of arresting him now."

Our official detectives may blunder in the matter of intelligence, but never in that of courage. Gregson climbed the stair to arrest this desperate murderer with the same absolutely quiet and businesslike bearing with which he would have ascended the official staircase of Scotland Yard. The Pinkerton man had tried to push past him, but Gregson had firmly elbowed him back. London dangers were the privilege of the London force.

The door of the left-hand flat upon the third landing was standing ajar. Gregson pushed it open. Within all was absolute silence and darkness. I struck a match and lit the detective's lantern. As I did so, and as the flicker steadied into a flame, we all gave a gasp of surprise. On the deal boards of the carpetless floor there was outlined a fresh track of blood. The red steps pointed towards us and led away from an inner room, the door of which was closed. Gregson flung it open and held his light full blaze in front of him, while we all peered eagerly over his shoulders.

In the middle of the floor of the empty room was huddled the figure of an enormous man, his clean-shaven, swarthy face grotesquely horrible in its contortion and his head encircled by a ghastly crimson halo of blood, lying in a broad wet circle upon the white woodwork. His knees were drawn up, his hands thrown out in agony, and from the center of his broad, brown, upturned throat there projected the white haft of a knife driven blade-deep into his body. Giant as he was, the man must have gone down like a poleaxed ox before that terrific blow. Beside his right hand a most formidable horn-handled, two-edged dagger lay upon the floor, and near it a black kid glove.

"By George! it's Black Gorgiano himself!" cried the American detective. "Someone has got ahead of us this time."

"Here is the candle in the window, Mr. Holmes," said Gregson. "Why, whatever are you doing?"

Holmes had stepped across, had lit the candle, and was passing it backward and forward across the windowpanes. Then he peered into the darkness, blew the candle out, and threw it on the floor.

"I rather think that will be helpful," said he. He came over and stood in deep thought while the two professionals were examining the body. "You say that three people came out from the flat while you were waiting downstairs," said he at last. "Did you observe them closely?"

"Yes, I did."

"Was there a fellow about thirty, black-bearded, dark, of middle size?"

"Yes; he was the last to pass me."

"That is your man, I fancy. I can give you his description, and we have a very excellent outline of his footmark. That should be enough for you."