But on this occasion the keys did not go out of his custody from the time when he locked up the safe, after depositing the diamonds in it, to the time when it was opened by him on the following morning." "And was there anything that tended to throw suspicion upon anyone ?" asked Thorndyke.
"Why, yes," said Mr.Lawley, with an uncomfortable glance at his client, "unfortunately there was.

It seemed that the person who abstracted the diamonds must have cut or scratched his thumb or finger in some way, for there were two drops of blood on the bottom of the safe and one or two bloody smears on a piece of paper, and, in addition, a remarkably clear imprint of a thumb." "Also in blood ?" asked Thorndyke.
"Yes.

The thumb had apparently been put down on one of the drops and then, while still wet with blood, had been pressed on the paper in taking hold of it or otherwise." "Well, and what next ?" "Well," said the lawyer, fidgeting in his chair, "to make a long story short, the thumb-print has been identified as that of Mr.Reuben Hornby." "Ha!" exclaimed Thorndyke.

"The plot thickens with a vengeance.

I had better jot down a few notes before you proceed any further." He took from a drawer a small paper-covered notebook, on the cover of which he wrote "Reuben Hornby," and then, laying the book open on a blotting-pad, which he rested on his knee, he made a few brief notes.
"Now," he said, when he had finished, "with reference to this thumb-print.