"When did this extraordinary conversation take place?"
"Last night, at the Bures ball. It wasn't as sudden as it sounds. I began to wonder about Simon long before that, and I challenged him about it because of something he said about knowing I wasn't Patrick, and he laughed and boasted about it."
"I think that the setting of this scene does a lot to explain it."
"You mean you think we were drunk?"
"Not exactly. Elated, shall we say. And you challenged Simon on the subject, and Simon with his perverted sense of mischief provided you with what you expected from him."
"Do you really believe I have as little intelligence as that?" Brat asked quietly.
"It surprises me, I must admit. I have always considered you to be highly intelligent."
"Then believe me, I am not here because of a piece of fooling on Simon's part. Patrick didn't commit suicide. Simon killed him. Deliberately. And what is more, I know how he did it."
And he told him.
"But Brat, you have no evidence even now. That is theory, what you have just told me. An ingenious and likely theory, I admit. It has the merit of simplicity. But you have no evidence whatsoever."