Poole turned the matter over quickly in his mind. He felt pretty sure that this was the explanation of how the murder had been committed. Somebody who knew about the aneurism and realized the nature of the blow that could cause it to burst without penetrating, or even abrazing the skin, had devised this missile for the purpose. What weapon could throw such a missile? A shot-gun was out of the question—the explosion must have been heard; an air-rifle was probably precluded by the size of the bore; a catapult? Probably something of that kind; for a moment its exact nature was not of vital importance. What did the tag of cord imply? Probably that the bullet—a significant object if found near the spot—had been attached to a cord which could be used for pulling it back into the car after the shot was fired. The bullet had evidently fallen on to the grating and dropped through the bars, the cord breaking when the strain came. In that case, surely the murderer would have come back to look for and, if possible, remove such a dangerous clue. Poole turned to the scavenger. “You didn’t see anyone search around here, I suppose,” he asked. “Can’t say I did, sir.” The police-constable—Lolling’s relief—who had been standing silently by all this time, except when he moved on two passers-by whose curiosity had been aroused by the unusual group, now cleared his throat and made his first contribution to the discussion. “I wouldn’t say but what I’d seen the chap myself, sir,” he said, with ponderous gravity. Poole looked at him questioningly. The constable continued at his own pace. “I was on duty here on the night in question, sir. I relieved Police-Constable Lolling at about 8 p. m. and he informed me of the incident” (he accented the second syllable). “I took no great note of what appeared to be a death from natural causes. Soon after I came on duty I noticed a bloke—a person, sir—a male person, dressed like a tramp he was—shuffling along down the gutter and looking about him—scavenging cigarette-ends, I took it to be. I was standing not far from here and he didn’t hang about. About an hour later I was not far away—under those trees to be exact—there was a slight drizzle—when I saw the same party come back. He hung about here a bit this time and as I don’t like that sort of party hanging about on my beat, I passed him on.” “Did he say anything?” “Nothing, sir.” “What did he look like?” “I couldn’t really say, sir. Just a tramp.” “Had he a moustache—a beard?” “There again I couldn’t say, sir, at this distance of time. He was a dirty sort of bloke—that’s all I could swear to.”