“Have you ever seen the Marquis, Mademoiselle Zia?”

“Once,” said the girl. “But not very well,” she added. “It was through a keyhole.”

“That always presents difficulties,” said Poirot sympathetically, “but all the same you saw him. You would know him again?”

Zia shook her head.

“He wore a mask,” she explained.

“Young or old?”

“He had white hair. It may have been a wig, it may not. It fitted very well. But I do not think he was old. His walk was young, and so was his voice.”

“His voice?” said Poirot thoughtfully. “Ah, his voice! Would you know it again, Mademoiselle Zia?”

“I might,” said the girl.