The Cat's Eye by R. Austin Freeman — Read

As the cab rolled swiftly through the quietening streets I turned over once more the two statements that had been made by Superintendent Miller and compared them. Together they had yielded to the amazingly quick intelligence of my friend Thorndyke something that the speaker had not intended to convey. What was the something? The first statement had set forth that the fingerprints were those of Joseph Hedges -- or Moakey, as his associates had nicknamed him; the second had set forth that the fingerprints were not his but those of some person who had yet to be identified. The two statements contradicted one another, of course, but the first was admittedly based upon a mistake. What was the fact that emerged from the contradiction?

I revolved the question again and again without seeing any glimmer of light. And then, suddenly, the simple explanation burst upon me. Of course! The prints were those of fingers smeared with Japanese wax. But Japanese wax is used for making furniture polish. There was the solution of this profound mystery. They were Mrs Benham's fingerprints -- or perhaps those of the murdered man -- made in the process of applying furniture polish to the cabinet. This, the only clue, evaporated into a myth and left Miss Blake's identification the only link with the vanished murderer.