Whyland, having cautioned the man to say nothing until the inquest, left the house and walked into the confectioner’s shop. Here he interviewed Mr. Briggs and his daughter Marjorie, and obtained from them the story of Mr. Martin’s arrival at Number 407, and of the telephone message from Mr. Lacey. By this time the body had been conveyed to the mortuary, and Whyland set to work to examine the contents of the dead man’s pockets. His most interesting discoveries were the letter which he had received on Saturday morning and the missing key of Number 407. The doctor arrived and performed his post-mortem, which confirmed the suspicions he had already formed. “Prussic acid, right enough, and a pretty powerful dose by the look of it. The queer thing about it is that he seems to have died from breathing the vapour rather than from swallowing the stuff. Looks as if he’d uncorked a bottle of the strong acid and sniffed at it. You didn’t see anything of the kind lying about the cellar, I suppose?” Whyland shook his head. “No, I didn’t,” he replied. “The only thing I found lying about was a loaded automatic which hadn’t been fired.” “What did I tell you?” said the doctor triumphantly. “Suicide, without a doubt. He took a pistol with him in case the stuff didn’t act. You’re suggesting that anybody murdered a powerful man like that by making him inhale prussic acid against his will, are you? Why, the idea’s absurd.” Inspector Whyland left the mortuary in a very thoughtful frame of mind, and returned to the police station. Here he set the telephone to work and invoked the aid of his colleagues. By the middle of the afternoon he had collected some interesting information respecting both Martin and Lacey, upon which he began to build up his own theory as to the former’s death. Mr. Martin had carried on a wine merchant’s business at 407, Praed Street, until fifteen years before. He had then moved to the Barbican, where he employed two clerks and a couple of packers. He had never married, and lived at a boarding house in Streatham. He had more than once gone away for the week-end without notice, and his absence had therefore caused no concern. He was not known to have any enemies, although more than once there had been some unsavoury rumours in circulation as to his dealings with girls whom he had engaged as his secretaries. His movements on Saturday morning were traced from the time he left his office to his reaching Aldersgate station. Finally, as a result of the hint contained in the letter signed John Lacey, the police had searched his office, and had found there certain papers which threw a flood of light upon a long sequence of jewel robberies extending back for the last twenty years.