“Which do you think he is, Mr. Gillingham?” said Cayley, looking at him steadily.
“Mark? It’s absurd,” said Bill impetuously.
“Bill’s loyal, you see, Mr. Cayley.”
“And you owe no loyalty to anyone concerned?”
“Exactly. So perhaps I might be too frank.”
Bill had dropped down on the grass, and Cayley took his place on the seat, and sat there heavily, his elbows on his knees, his chin on his hands, gazing at the ground.
“I want you to be quite frank,” he said at last. “Naturally I am prejudiced where Mark is concerned. So I want to know how my suggestion strikes you—who have no prejudices either way.”
“Your suggestion?”
“My theory that, if Mark killed his brother, it was purely accidental—as I told the Inspector.”
Bill looked up with interest.
“You mean that Robert did the holdup business,” he said, “and there was a bit of a struggle, and the revolver went off, and then Mark lost his head and bolted? That sort of idea?”
“Exactly.”
“Well, that seems all right.” He turned to Antony. “There’s nothing wrong with that, is there? It’s the most natural explanation to anyone who knows Mark.”
Antony pulled at his pipe.
“I suppose it is,” he said slowly. “But there’s one thing that worries me rather.”
“What’s that?” Bill and Cayley asked the question simultaneously.
“The key.”
“The key?” said Bill.
Cayley lifted his head and looked at Antony. “What about the key?” he asked.
“Well, there may be nothing in it; I just wondered. Suppose Robert was killed as you say, and suppose Mark lost his head and thought of nothing but getting away before anyone could see him. Well, very likely he’d lock the door and put the key in his pocket. He’d do it without thinking, just to gain a moment’s time.”
“Yes, that’s what I suggest.”
“It seems sound enough,” said Bill. “Sort of thing you’d do without thinking. Besides, if you are going to run away, it gives you more of a chance.”
“Yes, that’s all right if the key is there. But suppose it isn’t there?”
The suggestion, made as if it were already an established fact, startled them both. They looked at him wonderingly.
“What do you mean?” said Cayley.
“Well, it’s just a question of where people happen to keep their keys. You go up to your bedroom, and perhaps you like to lock your door in case anybody comes wandering in when you’ve only got one sock and a pair of braces on. Well, that’s natural enough. And if you look round the bedrooms of almost any house, you’ll find the keys all ready, so that you can lock yourself in at a moment’s notice. But downstairs people don’t lock themselves in. It’s really never done at all. Bill, for instance, has never locked himself into the dining-room in order to be alone with the sherry. On the other hand, all women, and particularly servants, have a horror of burglars. And if a burglar gets in by the window, they like to limit his activities to that particular room. So they keep the keys on the outside of the doors, and lock the doors when they go to bed.” He knocked the ashes out of his pipe, and added, “At least, my mother always used to.”
“You mean,” said Bill excitedly, “that the key was on the outside of the door when Mark went into the room?”
“Well, I was just wondering.”
“Have you noticed the other rooms—the billiard-room, and library, and so on?” said Cayley.
“I’ve only just thought about it while I’ve been sitting out here. You live here—haven’t you ever noticed them?”
Cayley sat considering, with his head on one side.
“It seems rather absurd, you know, but I can’t say that I have.” He turned to Bill. “Have you?”
“Good Lord, no. I should never worry about a thing like that.”
“I’m sure you wouldn’t,” laughed Antony. “Well, we can have a look when we go in. If the other keys are outside, then this one was probably outside too, and in that case—well, it makes it more interesting.”
Cayley said nothing. Bill chewed a piece of grass, and then said, “Does it make much difference?”
“It makes it more hard to understand what happened in there. Take your accidental theory and see where you get to. No instinctive turning of the key now, is there? He’s got to open the door to get it, and opening the door means showing his head to anybody in the hall—his cousin, for instance, whom he left there two minutes ago. Is a man in Mark’s state of mind, frightened to death lest he should be found with the body, going to do anything so foolhardy as that?”
“He needn’t have been afraid of me,” said Cayley.
“Then why didn’t he call for you? He knew you were about. You could have advised him; Heaven knows he wanted advice. But the whole theory of Mark’s escape is that he was afraid of you and of everybody else, and that he had no other idea but to get out of the room himself, and prevent you or the servants from coming into it. If the key had been on the inside, he would probably have locked the door. If it were on the outside, he almost certainly wouldn’t.”
“Yes, I expect you’re right,” said Bill thoughtfully. “Unless he took the key in with him, and locked the door at once.”
“Exactly. But in that case you have to build up a new theory entirely.”
“You mean that it makes it seem more deliberate?”
“Yes; that, certainly. But it also seems to make Mark out an absolute idiot. Just suppose for a moment that, for urgent reasons which neither of you know anything about, he had wished to get rid of his brother. Would he have done it like that? Just killed him and then run away? Why, that’s practically suicide—suicide whilst of unsound mind. No.
