There was another silence; then the girl said, “My father gave you a hint the other day.”

“It was very kind of him.”

“I do not think,” said Zia slowly, “that there is anything that I can add to that.”

If Poirot was disappointed he did not show it. Not a muscle of his face changed.

“ Eh bien! ” he said cheerfully, “then we must talk of other things.”

And he proceeded to chat gaily. The girl was distraite, however, and her answers were mechanical and not always to the point. It was when they were approaching the Casino once more that she seemed to come to a decision.

“ M. Poirot?”