"I know. I lied the other day. It was my wife's compartment I went into."
"Ah," said Katherine.
"It's difficult to explain just why I went in, but I'll try. I did it on an impulse. You see, I was more or less spying on my wife. I kept out of sight on the train. Mirelle had told me that my wife was meeting the Comte de la Roche in Paris. Well, as far as I had seen, that was not so. I felt ashamed, and I thought suddenly that it would be a good thing to have it out with her once and for all, so I pushed open the door and went in."
He paused.
"Yes," said Katherine gently.
"Ruth was lying on the bunk asleep—her face was turned away from me—I could see only the back of her head. I could have waked her up, of course. But suddenly I felt a reaction. What, after all, was there to say that we hadn't both of us said a hundred times before? She looked so peaceful lying there. I left the compartment as quietly as I could."
"Why lie about it to the police?" asked Katherine.
"Because I'm not a complete fool. I've realized from the beginning that, from the point of view of motive, I'm the ideal murderer. If I once admitted that I had been in her compartment just before she was murdered, I'd do for myself once and for all."
"I see."
Did she see? She could not have told herself. She was feeling the magnetic attraction of Derek's personality, but there was something in her that resisted, that held back....