The Red Thumb Mark
"A fortnight ago Mr. Hornby was advised that a parcel of stones had been despatched by the Elmina Castle, and it appeared that the parcel was an unusually large one and contained stones of exceptional size and value. Under these circumstances Mr. Reuben was sent down to the docks at an early hour in the hope the ship might arrive in time for the stones to be lodged in the bank at once. Unfortunately, however, this was not the case, and the diamonds had to be taken to the works and locked up in the safe."
"Who placed them in the safe?" asked Thorndyke.
"Mr. Hornby himself, to whom Mr. Reuben deliver