"So you changed into swimming things, walked down to the beach with your brother's coat over you, and — then what?"
"She was a fair way out. I went in, swam up to her, and drowned her."
"How?"
"She said, 'Hello, Judy. I said, 'Hello. I gave her a light tap on the chin. My brother taught me where to hit a person's chin, so as to addle them. Then I dived under her and pulled her through the water by the heels until she was drowned."
"Very neat," Grant said. "You've thought it all out, haven't you? Have you invented a motive for yourself, too?"
"Oh, I just didn't like her. I hated her, if you want to know. Her success and her looks and her self-sufficiency. She got in my hair until I couldn't bear it another day."
"I see. And will you explain why, having achieved the practically perfect murder, you should calmly come here and put a noose around your neck?"
"Because you've got someone for it."
"You mean because we've got Robert Tisdall. And that explains everything. And now having wasted some precious minutes of my time, you might recompense me and rehabilitate yourself at the same time, by telling me what you know of Tisdall."
"I don't know anything. Except that he would be the very last person in the world to commit a murder. For any reason."