"But you say that the housemaid, when she came to clean the room, found the door locked from the outside?" I remarked. The reason I cannot tell, but somehow, while we had been speaking, I thought I had detected a curious mysterious evasiveness in the Captain's manner. Was he telling all he knew? "Yes," he said. "It was undoubtedly locked from the outside--a most mysterious fact." "Why mysterious?" I queried. "If Nicholson wished to commit suicide in mysterious circumstances, he could easily have arranged that he should be found behind locked doors. He had only to pass out by the door, lock it, and re-enter by the library window again, and bar that. I noticed as I came in that there is a spring-lock on the front door--so that it locks itself when closed!" "Ah! I had not thought of that," the Captain declared. "Of course, by such proceeding he would have been found locked in." "But you have suspicion of foul play," I said; "you may as well admit that, Captain Cardew." "Well, I see no good in concealing it," he said, with a smile. "To tell the truth now, after well weighing the facts for more than twenty-four hours, I have, I admit, come to a rather different conclusion to that of the medical men." "And I agree with you," I declared. "One point we have to consider is what occupied poor Guy from the time when he left you until two o'clock. He would not take an hour and a half to read a newspaper." "No, but he might have been reading something else. He was not writing letters, for the same thought occurred to me, and I searched for any letters he might have written, but I could find none." "The question arises whether he returned to the library in order to meet somebody there in secret," I exclaimed. "They may have passed in by the window to meet him, and afterwards out by the door, and eventually by the front door." His round face, with the slight fair moustache, instantly changed. "By Jove! I've never thought of that!" he gasped. "Then your theory is that from half-past twelve till two he was not alone, eh? What causes you to suspect that he did not die of natural causes, Mr Kemball? I've been quite frank with you; will you not be equally straightforward with me?" "Well, I have strong reasons for believing that it was to the interest of certain persons that he should die suddenly," I said; "that's all." "Will you not name the persons?" he asked. "Not until I obtain proof. I may be mistaken. I may be grossly misjudging perfectly innocent persons, therefore I make no specific charge against anybody," was my calm reply, as I stood gazing around the large sombre old room, whence a beautiful view of the long avenue and the park was spread. It was a quiet, silent, restful apartment, in which the previous owner--a great politician and writer--had spent many studious hours. "But if you entertain any well-founded suspicions, ought you not to put them to the police?"