"I fancy that is quite obvious," said Mr. Cunningham, gravely. "Why, my son Alec had not yet gone to bed, and he would certainly have heard anyone moving about."

"Where was he sitting?"

"I was sitting smoking in my dressing-room."

"Which window is that?"

"The last on the left, next my father's."

"Both your lamps were lit, of course?"

"Undoubtedly."

"There are some very singular points here," said Holmes, smiling. "Is it not extraordinary that a burglar—and a burglar who had had some previous experience—should deliberately break into a house at a time when he could see from the lights that two of the family were still afoot?"

"He must have been a cool hand."

"Well, of course, if the case were not an odd one we should not have been driven to ask you for an explanation," said Mister Alec. "But as to your idea that the man had robbed the house before William tackled him, I think it a most absurd notion. Shouldn't we have found the place disarranged and missed the things which he had taken?"