He leaned back in his chair and watched the suggestion slowly take effect. No one knew better than Hercule Poirot that the class to which Mason belongs cannot be hurried. He must give her time to get rid of her own preconceived ideas. At the end of three minutes she spoke:

“Well, of course, sir, it might be so. I never thought of it that way. The master is tall and dark, and just about that build. It was seeing the hat and coat that made me say it was a gentleman from outside. Yes, it might have been the master. I would not like to say either way I’m sure.”

“Thank you very much, Mademoiselle. I shall not require you any further. Ah, just one thing more.” He took from his pocket the cigarette case he had already shown to Katherine. “Is that your mistress’s case?” he said to Mason.

“No, sir, it is not the mistress’s⁠—at least⁠—”

She looked suddenly startled. An idea was clearly working its way to the forefront of her mind.