"You've got no right to ask me that, sir, and you know it. What's more, I'll have to warn you both -"
"- to keep our mouths shut! You needn't trouble!"
"But the knife!" Mathilda said. "I never saw it! What could he have done with that?"
"Easy enough to have concealed it from you!" Stephen said. "Up his sleeve, or even flat against the inside of his arm, with the hilt held downwards in the palm of his hand. You'd never see it!" He turned to the Inspector. "Would it have been possible for my uncle to have walked upstairs after having been stabbed?"
"A doctor could answer that better than I can, sir."
"Nevertheless, that is what you suspect. What put you on to it?"
"When I've proved it to my satisfaction, sir, maybe I'll tell you. Until then, I'm asking you and Miss Clare to behave as though we hadn't had this highly illuminating interview."
"You needn't worry!" Stephen said, his eyes glittering. "Not for worlds would I do anything to impede the course of justice! Not - for - worlds!"
"I think," said Mathilda, rather shakily, "that I'll retire to my room with a headache. I don't feel like meeting Joseph, and I certainly couldn't act a part. I feel slightly sick."
"That's right, miss, you go upstairs," said Hemingway. "It's the best thing you could do."