Ravensdene Court by J.S. Fletcher

It was very evident that the inspector was considerably puzzled, not to say upset, by the disappearance of the tobacco-box, and I fancied that I saw the real reason of his discomfiture. He had poohpoohed Mr. Cazalette's almost senile eagerness about the thing, treating his request as of no importance; now he suddenly discovered that somebody had conceived a remarkable interest in the tobacco-box and had cleverly annexed it -- under his very eyes -- and he was angry with himself for his lack of care and perception. I was not indisposed to banter him a little.

"The second of your questions might be easily answered," I said. "The thing has been appropriated because somebody believes, as Mr. Cazalette evidently does, or did, that there may be a clue in those scratches, or marks, on the inside of the lid. But as to who it was that believed this, and managed to secrete the box -- that's a far different matter!"