"Well."
"Sorry, Tony; I'm dense this morning."
"In the car, Bill. And how near can the car get to Jallands?"
"About six hundred yards."
"Yes. And on his way to Middleston, on some business or other, Mark stops the car, walks six hundred yards down the hill to Jallands, says, 'Oh, by the way, Mrs. Norbury, I don't think I ever told you that I have a shady brother called Robert,' walks six hundred yards up the hill again, gets into the car, and goes off to Middleston. Is that likely?"
Bill frowned heavily.
"Yes, but I don't see what you're getting at. Likely or not likely, we know he did do it."
"Of course he did. All I mean is that he must have had some strong reason for telling Mrs. Norbury at once. And the reason I suggest is that he knew on that morning—Monday morning, not Tuesday—that Robert was coming to see him, and had to be in first with the news.
"But—but—"
"And that would explain the other point—his instantaneous decision at breakfast to tell you all about his brother. It wasn't instantaneous. He knew on Monday that Robert was coming, and decided then that you would all have to know."
"Then how do you explain the letter?"
"Well, let's have a look at it."
