"But why not have kept them in the passage?"

"He was frightened of the passage. Miss Norris knew about it."

"Well, then, in his own bedroom, or even, in Mark's. For all you
or I or anybody knew, Mark might have had two brown suits. He
probably had, I should think."

"Probably. But I doubt if that would reassure Cayley. The brown
suit hid a secret, and therefore the brown suit had to be hidden.
We all know that in theory the safest hiding-place is the most
obvious, but in practice very few people have the nerve to risk
it."

Bill looked rather disappointed.

"Then we just come back to where we were," he complained. "Mark
killed his brother, and Cayley helped him to escape through the
passage; either in order to compromise him, or because there was
no other way out of it. And he helped him by telling a lie about
his brown suit."

Antony smiled at him in genuine amusement.

"Bad luck, Bill," he said sympathetically. "There's only one
murder, after all. I'm awfully sorry about it. It was my fault
for--"

"Shut up, you ass. You know I didn't mean that."