This was the state of affairs towards the end of January. The police were completely baffled; Inspector Whyland, although he still favoured the theory he had evolved in the picture-house, had failed to find any evidence upon which he could act. He hardly knew whether to attribute Mr. Copperdock’s story of his meeting with the black sailor to pure hallucination, or to an attempt to divert suspicion from himself. In either case, it could be made to fit in with the theory that he had murdered Richard Pargent under the influence of what the psychologists called an imitative complex. Whyland redoubled his activities, and a most accurate watch was kept upon Mr. Copperdock’s movements. A month had elapsed since the murder of Richard Pargent when Mr. Jacob Martin, the prosperous wine merchant of the Barbican, opening his morning post in his comfortable office, came upon a typewritten envelope, marked “Private and Confidential.” He ripped it open with the paper cutter which lay upon his desk, and unfolded the letter it contained. It also was typewritten, on plain paper. Only the signature “John Lacey” was in ink. Mr. Martin, a portly, grey-haired man of between fifty and sixty, read the letter through twice, with a gathering frown upon his face. He had prospered exceedingly since the day when he had first set up in business for himself as a wine merchant, so much so that his competitors wondered at his success. There had, from time to time been rumours, quickly suppressed, to the effect that Mr. Martin had other means of livelihood than his ostensible business. But Mr. Martin was a remarkably astute man, and had hitherto managed to avoid undue inquisitiveness. And now, like a bolt from the blue, came this extraordinary letter. Confound John Lacey, and his prying habits, whoever he might be. That little cellar under the back office! How well he remembered it. It had been the scene of many most profitable transactions, had harboured treasures for which the police of two continents had searched in vain. For Mr. Martin was a receiver of stolen goods, not a mere general practitioner of the art, but a specialist whose services were utilized only by the aristocracy of thieves, and whose particular function was turning into cash only the most valuable jewellery.