But the girl over and over again asserted that she had heard it. She slept alone in a small room at the top of the second flight of stairs and had heard the sound quite distinctly. "When you heard it what did you do?" "I lay and listened." "For how long?" "Oh, quite a quarter of an hour, I should think. It was just before half-past one when I heard the noise, for the church clock struck almost immediately afterwards. The sound of the movement was such as I had never before heard at night, and at first I felt frightened. But I always lock my door, therefore I felt secure. The noise was just like someone creeping along very slowly, with one boot creaking." "But if it was so loud that you could hear it with your door closed, it is strange that no one else heard it," the detective-sergeant remarked dubiously. "I don't care what anybody else heard, I heard it quite plainly," the girl asserted. "How long did it continue?" asked the detective. "Oh, only just as though someone was stealing along the corridor. We often hear movements at nights, because Short is always astir at two o'clock, giving the master his medicine. If it hadn't ha' been for the creaking I should not have taken notice of it. But I lay quite wide awake for over half an hour--until Short came banging at our doors, telling us to get up at once, as we were wanted downstairs." "Well," exclaimed the inspector, "now, I want to ask all of you a very simple question, and wish to obtain an honest and truthful reply. Was any door or window left unfastened when you went to bed?" "No, sir," the cook replied promptly. "I always go round myself, and see that everything is fastened." "The front door, for example?" "I bolted it at Miss Ethelwynn's orders." "At what time?" "One o'clock. She told me to wait up till then, and if mistress did not return I was to lock up and go to bed." "Then the tragedy must have been enacted about half an hour later?" "I think so, sir." "You haven't examined the doors and windows to see if any have been forced?" "As far as I can see, they are just as I left them when I went to bed, sir." "That's strange--very strange," remarked the inspector, turning to us. "We must make an examination and satisfy ourselves." The point was one that was most important in the conduct of the inquiry. If all doors and windows were still locked, then the assassin was one of that strange household. Led by the cook, the officers began a round of the lower premises. One of the detectives borrowed the constable's bull's-eye and, accompanied by a second officer, went outside to make an examination of the window sashes, while we remained inside assisting them in their search for any marks. Ethelwynn had been called aside by one of the detectives, and was answering some questions addressed to her, therefore for an instant I found myself alone. It was the moment I had been waiting for, to secretly examine the clue I had obtained.