“All right, Alec; you can tell me all that in the proper place. Let me finish my story first. Well, having got so far, of course I asked myself—What light does this throw on Stanworth’s death? Does it give a definite pointer to any person? The answer was obvious. Mr. Alexander Grierson! I gasped at first, I can assure you, but when I got rather more used to the idea, daylight simply flooded in. First of all, there was your hanging back all the time; that began to take on a very significant aspect. Then there was your height and your strength, which fitted in very nicely, and I knew that your place in Worcestershire, where you must have spent most of your boyhood, is liberally supplied with lattice windows, so that you might be expected to be up to all the tricks of the trade regarding them. So far, in fact, so good.” “But what about that footprint? I thought I’d managed that rather neatly. By Jove, I remember the shock you gave me when you discovered that and the way I got out of the library that night. I’d thought that was absolutely untraceable.” “Yes, that did give me an awkward couple of minutes, until I remembered that you’d run back to get your pipe while I was talking to the chauffeur! And that’s where the second of my little pictures comes in. The scene flashed across my mind on that flower bed just after you had stepped on to the path when we were trying to find out who had been in the library and before you smoothed out the fresh footprints you’d made. The old and the new prints were absolutely identical, you see. I suppose I must have noted it subconsciously at the time without realizing its significance.” “I noticed it all right,” Alec said grimly. “It gave me a bad turn for the moment.” “After that all sorts of little things occurred to me,” Roger continued. “I began to test each of the facts I’d collected, and in each case the explanation was now obvious. Those letters, for instance. I knew they must have been posted between five and eight-thirty that morning; and at eight o’clock behold you coming back from the village and actually saying you’d been down there to post a letter!” “Couldn’t think of any other explanation on the spur of the moment,” Alec grinned ruefully. “Yes, and curiously enough I questioned the bookmaker motif at the time, didn’t I? Then there was your quite genuine anxiety to stop me from assuming complicity on the part of Mrs. Plant. I suppose you knew all the time about her and Stanworth, didn’t you?” Alec nodded. “I was present at the interview between them,” he said briefly. “The devil you were!” Roger exclaimed in surprise. “I never gathered that. She didn’t say anything about it.” “She didn’t know. I’ll tell you all about that. Anything else on your side?”