“But why should he want to throw it away?”

“Because it has now done its work, whatever it was, and he wants to wash his hands of the passage. He’d throw the passage away if he could. I don’t think it matters much one way or another, and I don’t suppose there’s anything to find in the cupboard, but I feel that we must look.”

“Do you still think Mark’s body might be there?”

“No. And yet where else can it be? Unless I’m hopelessly wrong, and Cayley never killed him at all.”

Bill hesitated, wondering if he dare advance his theory.

“I know you’ll think me an ass⁠—”

“My dear Bill, I’m such an obvious ass myself that I should be delighted to think you are too.”