"The lieutenant!" began Smith; then: "Oh! of course; Slattin used to be a police lieutenant!" "Well, sir, he--Mr. Slattin--had a sort of hold on this Singapore Charlie, and two years ago, when he first met him, he thought that with his aid he was going to pull off the biggest thing of his life--" "Forestall _me_, in fact?" "Yes, sir; but you got in first with the big raid--and spoiled it." Smith nodded grimly, glancing at the Scotland Yard man, who returned his nod with equal grimness. "A couple of months ago," resumed Burke, "he met Charlie again down East, and the Chinaman introduced him to a girl--some sort of an Egyptian girl." "Go on!" snapped Smith. "I know her." "He saw her a good many times--and she came here once or twice. She made out that she and Singapore Charlie were prepared to give away the boss of the Yellow gang--" "For a price, of course?" "I suppose so," said Burke; "but I don't know. I only know that I warned him." "H'm!" muttered Smith. "And now, what took place to-night?" "He had an appointment here with the girl," began Burke. "I know all that," interrupted Smith. "I merely want to know what took place after the telephone call." "Well, he told me to wait up, and I was dozing in the next room to the study--the dining-room--when the 'phone bell aroused me. I heard the lieutenant--Mr. Slattin--coming out, and I ran out too, but only in time to see him taking his hat from the rack--" "But he wears no hat!" "He never got it off the peg! Just as he reached up to take it, he gave a most frightful scream, and turned around like lightning as though some one had attacked him from behind!" "There was no one else in the hall?" "No one at all. I was standing down there outside the dining-room just by the stairs, but he didn't turn in my direction, he turned and looked right behind him--where there was no one--nothing. His cries were frightful." Burke's voice broke, and he shuddered feverishly. "Then he made a rush for the front door. It seemed as though he had not seen me. He stood there screaming; but, before I could reach him, he fell...." Nayland Smith fixed a piercing gaze upon Burke. "Is that all you know?" he demanded slowly. "As God is my judge, sir, that's all I know, and all I saw. There was no living thing near him when he met his death." "We shall see," muttered Smith. He turned to me. "What killed him, Petrie?" he asked shortly. "Apparently something which occasioned a minute wound on the left wrist," I replied, and, stooping, I raised the already cold hand in mine. A tiny, inflamed wound showed on the wrist; and a certain puffiness was becoming observable in the injured hand and arm. Smith bent down and drew a quick, sibilant breath. "You know what this is, Petrie?" he cried. "Certainly. It was too late to employ a ligature and useless to inject ammonia. Death was practically instantaneous. His heart...." There came a loud knocking and ringing.