“Allow me to explain.” Poirot raised his voice, though it was quite loud enough in the first place. “When we met here in this room before, I asked if anybody had taken sherry to Mr. Negus in his room. No one spoke up. Why did Thomas Brignell not say, ‘I did not take it up to his room, but I did fetch for him a glass of sherry?’ Poirot will tell you! He did not do so because he had doubts in his mind, and he did not want to risk saying something that was not true.

“Mr. Brignell was the only member of the hotel staff to see any of the three murder victims more than once—or, to be more precise, he had been led to believe that he had seen Richard Negus more than once. He knew that he had given a glass of sherry to a man calling himself Richard Negus who behaved as if he had encountered him before, but this man did not look like the Richard Negus that Thomas Brignell had met. Remember, Mr. Lazzari has told us that Mr. Brignell has an excellent memory for faces as well as names. That is why he did not speak up when I asked about the sherry! He was distracted by his thoughts. A voice in his head whispered: ‘It must have been him, the same man. But it was not him—I would have recognized him.’

“A few moments later, Mr. Brignell said to himself, ‘What kind of fool am I? Of course it was Richard Negus if he said that was his name! For once my memory lets me down. And besides, the man sounded just like Mr. Negus, with his educated English accent.’ It would seem incroyable to the scrupulously honest Thomas Brignell that anyone should wish to impersonate another in order to trick him.

“After reaching the conclusion that the man must have been Richard Negus, Mr. Brignell decides to stand up and tell me that he met Mr. Negus in the corridor at half past seven on the night of the murders, but he is too embarrassed to mention the sherry, because he fears he will seem an imbecile for sitting in silence in response to my earlier question about the drink. I would surely ask, in front of everybody, ‘Why did you not tell me this before?’ and Mr. Brignell would have been mortified to have to say, ‘Because I was too busy wondering how Mr. Negus came to have a different face the second time I encountered him.’ Mr. Brignell, can you confirm that what I am saying is true? There is no need to worry about looking like a fool. You were the opposite. It was a different face. It was a different man.”

“Thank goodness,” said Brignell. “Everything you have said is absolutely correct, Mr. Poirot.”