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 am 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。
〃Yes；〃 said Poirot encouragingly。
〃I think； sir … I can't be sure； but I think … it is a case that the mistress bought to give to the master。〃
〃Ah；〃 said Poirot in a nonmittal manner。
〃But whether she ever did give it to him or not； I can't say； of course。〃
〃Precisely；〃 said Poirot； 〃precisely。 That is all； I think； Mademoiselle。 I wish you good afternoon。〃
Ada Mason retired discreetly； closing the door noiselessly behind her。
Poirot looked across at Van Aldin； a faint smile upon his face。 The millionaire looked thunderstruck。
〃You think … you think it was Derek？〃 he queried； 〃but … everything points the other way。 Why； the Count has actually been caught red…handed with the jewels on him。〃
〃No。〃
〃But you told me …〃
〃What did I tell you？〃
〃That story about the jewels。 You showed them to me。〃
〃No。〃
Van Aldin stared at him。
〃You mean to say you didn't show them to me。〃
〃No。〃
〃Yesterday … at the tennis？〃
〃No。〃
〃Are you