"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."

"Yes. But isn't it overdoing it rather to make him change his
underclothes and everything? It wastes a good deal of time, you
know."

Bill was pulled up short, and said, "Oh!" in great
disappointment.

"No, it's not as bad as that, Bill," said Antony with a smile.
"I daresay the underclothes could be explained. But here's the
difficulty. Why did Mark need to change from brown to blue, or
whatever it was, when Cayley was the only person who saw him in
brown?"

"The police description of him says that he is in a brown suit."

"Yes, because Cayley told the police. You see, even if Mark had