The Classic Mystery Collection - Arthur Conan Doyle [219]
Now let us consider the alibi. If Manderson was in the house that night, and if he did not leave it until some time after 12.30, Marlowe could not by any possibility have had a direct hand in the murder. It is a question of the distance between Marlstone and Southampton. If he had left Marlstone in the car at the hour when he is supposed to have done so--between 10 and 10.30--with a message from Manderson, the run would be quite an easy one to do in the time. But it would be physically impossible for the car--a 15 h.p. four-cylinder Northumberland, an average medium-power car--to get to Southampton by half-past six unless it left Marlstone by midnight at latest. Motorists who will examine the road-map and make the calculations required, as I did in Manderson's library that day, will agree that on the facts as they appeared there was absolutely no case against Marlowe.
But even if they were not as they appeared; if Manderson was dead by eleven o'clock, and if at about that time Marlowe impersonated him at White Gables; if Marlowe retired to Manderson's bedroom--how can all this be reconciled with his appearance next morning at Southampton? He had to get out of the house, unseen and unheard, and away in the car by midnight. And Martin, the sharp-eared Martin, was sitting up until 12.30 in his pantry, with the door open, listening for the telephone bell. Practically he was standing sentry over the foot of the staircase, the only staircase leading down from the bedroom floor.
With this difficulty we arrive at the last and crucial phase of my investigation. Having the foregoing points clearly in mind, I spent the rest of the day before the inquest in talking to various persons and in going over my story, testing it link by link. I could only find the one weakness which seemed to be involved in Martin's sitting up until 12.30; and since his having been instructed to do so was certainly a part of the plan, meant to clinch the alibi for Marlowe, I knew there must be an explanation somewhere. If I could not find that explanation, my theory was valueless. I must be able to show that at the time Martin went up to bed the man who had shut himself in Manderson's bedroom might have been many miles away on the road to Southampton.
I had, however, a pretty good idea already--as perhaps the reader of these lines has by this time, if I have made myself clear--of how the escape of the false Manderson before midnight had been contrived. But I did not want what I was now about to do to be known. If I had chanced to be discovered at work, there would have been no concealing the direction of my suspicions. I resolved not to test them on this point until the next day, during the opening proceedings at the inquest. This was to be held, I knew, at the hotel, and I reckoned upon having White Gables to myself so far as the principal inmates were concerned.
So in fact it happened. By the time the proceedings at the hotel had begun I was hard at work at White Gables. I had a camera with me. I made search, on principles well known to and commonly practised by the police, and often enough by myself, for certain indications. Without describing my search, I may say at once that I found and was able to photograph two fresh fingerprints, very large and distinct, on the polished front of the right-hand top drawer of the chest of drawers in Manderson's bedroom; five more (among a number of smaller and less recent impressions made by other hands) on the glasses of the French window in Mrs Manderson's room, a window which always stood open at night with a curtain before it; and three more upon the glass bowl in which Manderson's dental plate had been found lying.
I took the bowl with me from White Gables. I took also a few articles which I selected from Marlowe's bedroom, as bearing the most distinct of the innumerable fingerprints which are always