“I knew about the arrangement whereby the keys were kept at the sweet shop. I had announced that I was going into the country that day, travelling into Essex by the London, Tilbury and Southend from Fenchurch Street. I took the Underground, apparently to Aldgate, but got out at Aldersgate Street. From here I walked down the Barbican, saw Martin leave his office, go to lunch, and finally book at Aldersgate Street to Praed Street. I immediately telephoned from one of the boxes there to Mr. Briggs, who had the keys, saying that I was the tenant of Number 407, and asking him to look out for a Mr. Martin, and give him the keys. I then went on to Fenchurch Street, spent a happy and profitable day in the country, and returned home to hear of the death of Mr. Martin. I was, I confess, slightly annoyed to find that it had been attributed to suicide. But then, I had never anticipated that Martin would bring an automatic with him. But perhaps I weary you with these details, Dr. Priestley?” “Not in the least!” replied the Professor fervently. He glanced furtively at the clock. It was already past ten o’clock. Chapter XXII The Death Chamber “What I have to tell you now may interest you more nearly, Dr. Priestley,” continued the Black Sailor. “Having disposed of five of my intended victims, I had to remove Copperdock. But I wished first of all to concentrate as much suspicion as possible on him before his death. You will perceive the idea, no doubt. If the murders were to cease with Copperdock’s death, there being already a vague suspicion that he had caused them, further enquiries would not be pursued very briskly. “For this reason, I appeared to Copperdock that evening as he was coming out of the Cambridge Arms. The disguise was very imperfect, since I had merely smeared the dye on my beard in the street, and the scar was made of sticking-plaster. It would not have borne a moment’s close inspection, but it was good enough for Copperdock, as I felt sure it would be. I escaped from him without difficulty, and, having taken a wet sponge with me, removed the scar and dye at the first opportunity and came quietly home. I beat Mr. Copperdock by about five minutes. “As I had expected, he told Whyland the story of his adventure, and I was in a position to swear that he and I had been alone in the street. The result was to discredit his veracity still further. I then thought it time to act. You will remember that Copperdock said he found a numbered counter on his bed? That was the exact truth, although it seemed impossible, and nobody believed him. But it was capable of the simplest explanation in the world. Look here.”