“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?”

“He didn’t appear to be.”

“Right . . . .  Now then, he arrived, you say, about three o’clock?”

“Yes, about that.”

“Who was in the house then?”

“Mark and myself, and some of the servants.  I don’t know which.  Of course, you will ask them directly, no doubt.”

“With your permission.  No guests?”

“They were out all day playing golf,” explained Cayley.  “Oh, by the way,” he put in, “if I may interrupt a moment, will you want to see them at all?  It isn’t very pleasant for them now, naturally, and I suggested—­” he turned to Antony, who nodded back to him.  “I understand that they want to go back to London this evening.  There’s no objection to that, I suppose?”

“You will let me have their names and addresses in case I want to communicate with them?”

“Of course.  One of them is staying on, if you would like to see him later, but they only came back from their golf as we crossed the hall.”

“That’s all right, Mr. Cayley.  Well, now then, let’s go back to three o’clock.  Where were you when Robert arrived?”

Cayley explained how he had been sitting in the hall, how Audrey had asked him where the master was, and how he had said that he had last seen him going up to the Temple.

“She went away, and I went on with my book.  There was a step on the stairs, and I looked up to see Mark coming down.  He went into the office, and I went on with my book again.  I went into the library for a moment, to refer to another book, and when I was in there I heard a shot.  At least, it was a loud bang, I wasn’t sure if it was a shot.  I stood and listened.  Then I came slowly to the door and looked out.  Then I went back again, hesitated a bit, you know, and finally decided to go across to the office, and make sure that it was all right.  I turned the handle of the door and found it was locked.  Then I got frightened, and I banged at the door, and shouted, and—­well, that was when Mr. Gillingham arrived.”  He went on to explain how they had found the body.

The inspector looked at him with a smile.

“Yes, well, we shall have to go over some of that again, Mr. Cayley.  Mr. Mark, now.  You thought he was in the Temple.  Could he have come in, and gone up to his room, without your seeing him?”

“There are back stairs.  He wouldn’t have used them in the ordinary way, of course.  But I wasn’t in the hall all the afternoon.  He might easily have gone upstairs without my knowing anything about it.”