“I’ll spare you the technical language,” I said. “We’ll keep that for the inquest. The blow was delivered by a right-handed man standing behind him, and death must have been instantaneous. By the expression on the dead man’s face, I should say that the blow was quite unexpected. He probably died without knowing who his assailant was.”

“Butlers can creep about as soft-footed as cats,” said Inspector Davis. “There’s not going to be much mystery about this crime. Take a look at the hilt of that dagger.”

I took a look.

“I dare say that they’re not apparent to you, but I can see them clearly enough.” He lowered his voice. “ Fingerprints! ”

He stood off a few steps to judge his effect.

“Yes,” I said mildly. “I guessed that.”