“I will stop when I am ready,” said Poirot. “You were a regular visitor to Pleasant’s Coffee House, mademoiselle. The waitresses have said so. They talk about their customers a great deal in their absence. I expect you heard them speak about me: the fussy European gentleman with the mustache who used to be a policeman on the Continent—and my friend Catchpool here, from Scotland Yard. You heard them say that I dine at Pleasant’s every Thursday evening at half past seven precisely. Oh, yes, mademoiselle, you knew where to find me, and you knew that Hercule Poirot would be perfect for your devious purposes! You arrived at the coffee house in an apparent state of terror, but it was all a lie, an act! You stared out of the window for a long time, as if fearful of someone in pursuit, but you cannot have seen anything out of that window except the reflection of the room that you were in. And one of the waitresses, she saw your eyes reflected and saw that you were watching her, not the street. You were calculating, were you not? ‘Will anyone suspect that I am feigning my state of distress? Will that sharp-eyed waitress guess the truth and prevent my plan from being successful?’ ”

I rose to my feet. “Poirot, I don’t doubt that you’re right, but you can’t simply go on at the poor woman without allowing her to say a word in her defense.”

“Be quiet, Catchpool. Have I not just explained to you that Miss Hobbs is excellent at creating an appearance of great unhappiness while, underneath, her true self is composed and calculating?”

“You are a cold-hearted man!” Jennie wailed.

“Au contraire, mademoiselle. In due course you will have your turn to speak, you may rest assured, but first I have another question for you. You said to me, ‘Oh, please let no one open their mouths!’ How did you know that Nancy Ducane, after killing her three victims, had placed cufflinks in their mouths? It seems to me odd that you should know this. Did Mrs. Ducane threaten that it would happen? I can imagine a murderer threatening violence in order to scare—‘If I catch you, I will cut your throat,’ or something of that nature—but I cannot imagine a killer saying, ‘After I have murdered you, I intend to place a monogrammed cufflink in your mouth.’ I cannot imagine any person saying that, and I am a man of considerable imagination!