He had pencilled on it some particulars relating to the diamonds, and laid it on the parcel before he closed up the safe." "Was anyone present when Mr.Hornby opened the safe in the morning ?" asked Thorndyke.
"No, he was alone," answered the lawyer.

"He saw at a glance that the diamonds were missing, and then he observed the paper with the thumb-mark on it, on which he closed and locked the safe and sent for the police." "Is it not rather odd that the thief did not notice the thumb-mark, since it was so distinct and conspicuous ?" "No, I think not," answered Mr.Lawley.

"The paper was lying face downwards on the bottom of the safe, and it was only when he picked it up and turned it over that Mr.Hornby discovered the thumb-print.
Apparently the thief had taken hold of the parcel, with the paper on it, and the paper had afterwards dropped off and fallen with the marked surface downwards--probably when the parcel was transferred to the other hand." "You mentioned," said Thorndyke, "that the experts at Scotland Yard have identified this thumb-mark as that of Mr.Reuben Hornby.

May I ask how they came to have the opportunity of making the comparison ?" "Ah!" said Mr.Lawley.

"Thereby hangs a very curious tale of coincidences.