I had become obsessed by the mystery of it all. I returned to Chiswick, and tried to give my mind to the details of my business, but all without avail. I saw that Pelham, my manager, was surprised at my apparent absent-mindedness. I knew it was incumbent upon me to go to the police-station, which was only a few hundred yards from me on the opposite side of the road, and tell the inspector on duty the whole story. Yet somehow the affair, with all its mysterious features, had fascinated me, and Kershaw Kirk most of all. The information was mine, and it was for me to solve this remarkable enigma. Kirk's absence from home, and his failure to communicate with me, showed that either he mistrusted me, or that he was purposely misleading me for the attainment of his own ends. He had sought my friendship and assistance, and yet next day he had abandoned me in doubt and ignorance. I managed to get through the day at the garage, and eagerly bought the evening paper, anxious to see whether the tragedy had become public property; but as yet it was unknown. I dined at home, and I suppose my manner was so preoccupied that Mabel, my wife, asked: "What's the matter, Harry? You seem unusually worried?" "Oh! I don't know, dear," I replied, trying to laugh. "I've had a lot of things to do at the office to-day," I added in excuse; "I've got to go back this evening." Mabel pouted, and I knew the reason. I had promised to run her and her sister over to Teddington to see some friends with whom we had promised to spend the evening. But I was in no mood for visiting friends. I went along to Kirk's house, and, finding him still absent, took the train from Hammersmith to Baker Street, and walked through Clarence Gate to Sussex Place. It had just struck nine when I halted at the Professor's door, but I drew back suddenly when I saw a tall, well-dressed, clean-shaven young man in hard felt hat and overcoat, standing in the doorway. He had rung, and was evidently awaiting an answer to his summons. The place was, I noticed, in darkness. Antonio had evidently omitted to switch on the light in the hall. What could that young man want at the house of death? Unfortunately, I had not been quick enough, for as I halted he turned upon me, realising that to call there was my intention. "This is strange!" he remarked to me, "I've been ringing here nearly half an hour, and can get no reply. Yet when I passed the front of the house there was a light in the small drawing-room. I've never before known the place to be left; there are always servants here, even if the Professor and his daughter are absent." It occurred to me that Antonio had detected him from within, and that he might be an unwelcome visitor. I recollected Kirk's strict injunctions to the faithful Italian. "Antonio may be out," I suggested. "But the maids would surely be at home," he argued. "I wonder if thieves are inside? I somehow suspect it," he whispered. "Why?"