Gimblet nodded philosophically.
"Is there anything else?" he asked.
Mark hesitated.
"There's a letter which arrived for Uncle Douglas this morning," he said, "which you may think worth looking at. I daresay it's of no importance, but it struck me as rather odd."
He took a letter out of his pocket and handed it to the detective, who opened it and read as follows:
"Si Milord ne rend pas ce qu'il ne doit pas garder, le coup de foudre lui tombera sur la tête."
There was no signature, nor any date.
Gimblet turned the sheet over thoughtfully. The message was typewritten on a piece of thin foreign paper; the postmark on the envelope was Paris, and the stamps French. He folded it again and replaced it in its cover.
"It seems the usual threatening anonymous communication," he observed.
"Have you any idea who it's from?"
Mark shook his head.