Directly he asked the question I knew that it was the doctor's face which had been there. "The subtle personality, Wigan." "When did you guess?" "I didn't guess--I didn't think it possible. Bates' disbelief in the supernatural made me a little suspicious, but I didn't think it possible. To-night--that ape--the whole plot--I could only think of Randall. There was no one else." We left the house at once, both of us in an excited state. The constable I had on special duty soon had several others with him, and before dawn No. 5 Manleigh Road was raided. It was only a garbled statement which got into the papers, and probably the whole truth will never be known; but I gradually gathered the main facts, partly from the doctor's confederates, partly from some of his victims. Dr. Randall, posing as a nerve specialist, and fully qualified to do so, had lived a double life. As a doctor he was respected and was fairly successful; as the head and organizer of a small army of miscreants he had been eminent for years. Under the guise of a respectable boarding-house, No. 5 had been used as the headquarters of the gang, and the operations had been so widespread, so all-embracing in the field of crime, that after the raid many mysteries which the police had failed to unravel were credited to Randall. Many of these he could have had nothing to do with, but he had quite enough to answer for. He seems to have exercised a kind of terrorism over his subordinates, or he would surely have been betrayed before. Exactly at what point my investigations had jeopardized his secret I could not find out, but he evidently thought it was in danger, and believing Quarles was responsible, he determined to get rid of him. I was told that he had made two attempts upon his life before the night he was introduced to him in the Temple. That night Quarles was followed when he left the Temple, and, as we know, was shot at in Savoy Street. This attempt failing, the doctor, who had already asked Quarles to dinner on the following night as an extra precaution, determined to use a method which had already proved successful. Quarles's enthusiasm for psychological research could hardly fail to tempt him into the trap. No. 7 Manleigh Road belonged to a man in the doctor's employment. It had been prepared for eventualities some time before--probably tragedies had occurred in the house which had never been heard of. The house agent was one of the gang, and when, either by mistake or because he could not help himself without causing undesirable comment, he let the house to the young married couple, they were frightened away. The house was then let to Greaves, a man who had become a danger to the doctor, and in due course he was found dead in his bed. Between the fireplace of the haunted room and that of the corresponding room in No. 5 part of the chimney wall had been removed, so that there was sufficient space for the ape to get from one room to the other.