"Had the place been broken into?" asked Thorndyke.

"No. The place was all locked up as usual, and the caretaker, who had
made his accustomed rounds, had heard nothing, and the safe was,
outwardly, quite undisturbed. It had evidently been opened with keys and
locked again after the stones were removed."

"And in whose custody were the keys of the safe?" inquired Thorndyke.

"Mr. Hornby usually kept the keys himself, but, on occasions, when he
was absent from the office, he handed them over to one of his
nephews--whichever happened to be in charge at the time. 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."