“As far as I remember, something like this: ‘Mark, your loving brother is coming to see you tomorrow, all the way from Australia. I give you warning so that you will be able to conceal your surprise, but not I hope, your pleasure. Expect him at three, or thereabouts.’ ”

“Ah!” The inspector copied it down carefully. “Did you notice the postmark?”

“London.”

“And what was Mark’s attitude?”

“Annoyance, disgust⁠—” Cayley hesitated.

“Apprehension?”

“N-no, not exactly. Or, rather, apprehension of an unpleasant interview, not of any unpleasant outcome for himself.”

“You mean that he wasn’t afraid of violence, or blackmail, or anything of that sort?”