“There was one thing in the case which had made the deepest impression both upon the servants and the police. This was the contortion of the Colonel’s face. It had set, according to their account, into the most dreadful expression of fear and horror which a human countenance is capable of assuming. More than one person fainted at the mere sight of him, so terrible was the effect. It was quite certain that he had foreseen his fate, and that it had caused him the utmost horror. This, of course, fitted in well enough with the police theory, if the Colonel could have seen his wife making a murderous attack upon him. Nor was the fact of the wound being on the back of his head a fatal objection to this, as he might have turned to avoid the blow. No information could be got from the lady herself, who was temporarily insane from an acute attack of brain-fever.
“From the police I learned that Miss Morrison, who you remember went out that evening with Mrs. Barclay, denied having any knowledge of what it was which had caused the ill-humor in which her companion had returned.
“Having gathered these facts, Watson, I smoked several pipes over them, trying to separate those which were crucial from others which were merely incidental. There could be no question that the most distinctive and suggestive point in the case was the singular disappearance of the door-key. A most careful search had failed to discover it in the room. Therefore it must have been taken from it. But neither the Colonel nor the Colonel’s wife could have taken it. That was perfectly clear. Therefore a third person must have entered the room. And that third person could only have come in through the window. It seemed to me that a careful examination of the room and the lawn might possibly reveal some traces of this mysterious individual. You know my methods, Watson. There was not one of them which I did not apply to the inquiry. And it ended by my discovering traces, but very different ones from those which I had expected. There had been a man in the room, and he had