Her lips twitched a little at that, but she said nothing.
"I had hoped that with your help we might agree on some explanation—less than the truth, perhaps, but sufficient to clear my brother. As it is, I fear I shall have to produce the proof I hold, and let matters take their course."
That, at last, struck under her guard. A dull flush crept up her cheeks; one hand tightened upon the handle of the churn, where she had rested it.
"What do you mean by proof?"
"I can prove that on the night of the 13th my brother slept in the room I occupied last night," said Wimsey, with calculated brutality.
She winced. "It is a lie. You cannot prove it. He will deny it. I shall deny it."
"He was not there?"
"No."
"Then how did this come to be wedged in the sash of the bedroom window?"
At sight of the letter she broke down, crumpling up in a heap against the table. The set lines of her face distorted themselves into a mere caricature of terror.