“None whatever. There is the scar to prove it, and I can produce the surgeon who attended Belfield at the time.”

The officer rubbed his head harder than before, and regarded Thorndyke with puckered brows.

“This is a teaser,” he growled, “it is indeed. What you say, sir, seems perfectly sound, and yet—there are those finger-prints on the window-glass. Now you can’t get finger prints without fingers, can you?”

“Undoubtedly you can,” said Thorndyke.

“I should want to see that done before I could believe even you, sir,” said Miller.

“You shall see it done now,” was the calm rejoinder. “You have evidently forgotten the Hornby case—the case of the Red Thumb-mark, as the newspapers called it.”

“I only heard part of it,” replied Miller, “and I didn’t really follow the evidence in that.”

“Well, I will show you a relic of that case,” said Thorndyke. He unlocked a cabinet and took from one of the shelves a small box labelled “Hornby,” which, being opened, was seen to contain a folded paper, a little red-covered oblong book and what looked like a large boxwood pawn.

“This little book,” Thorndyke continued, “is a ‘thumbograph’—a sort of finger-print album—I dare say you know the kind of thing.”

The superintendent nodded contemptuously at the little volume.