“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.”
“Well, then, suppose Mark did kill Robert, and Cayley helped him to escape, just as we thought at first. I know you proved afterwards that it was impossible, but suppose it happened in a way we don’t know about and for reasons we don’t know about. I mean, there are such a lot of funny things about the whole show that—well, almost anything might have happened.”
“You’re quite right. Well?”
“Well, then, this clothes business. Doesn’t that seem rather to bear out the escaping theory? Mark’s brown suit was known to the police. Couldn’t Cayley have brought him another one in the passage, to escape in, and then have had the brown one on his hands? And thought it safest to hide it in the pond?”
“Yes,” said Anthony thoughtfully. Then: “Go on.”
Bill went on eagerly:
“It all seems to fit in, you know. I mean even with your first theory—that Mark killed him accidentally and then came to Cayley for help. Of course, if Cayley had played fair, he’d have told Mark that he had nothing to be afraid of. But he isn’t playing fair; he wants to get Mark out of the way because of the girl. Well, this is his chance. He makes Mark as frightened as possible, and tells him that his only hope is to run away. Well, naturally, he does all he can to get him well away, because if Mark is caught, the whole story of Cayley’s treachery comes out.”