This time he produced from his pocket a paper packet, which he proceeded to unroll. From it he withdrew two sinister-looking blades, each stained a dull brown.

“These are the knives with which Tovey and Pargent were killed,” he said. “Don’t touch them, but tell me if you can tell one from the other.”

Mr. Ludgrove adjusted his spectacles, and bent over the knives. They were exactly similar, thin, with an extremely sharp point, about half an inch wide and eight inches long. Neither of them showed any sign of having ever possessed a handle.