“By Jove!”
“Well, of course that proved nothing; and the key business didn’t really prove anything, because whatever side of the door the other keys were, Mark might have locked his own private room from the inside sometimes. But I piled it on, and pretended that it was enormously important, and quite altered the case altogether, and having got Cayley thoroughly anxious about it, I told him that we should be well out of the way for the next hour or so, and that he would be alone in the house to do what he liked about it. And, as I expected, he couldn’t resist it. He altered the keys and gave himself away entirely.”
“But the library key was still outside. Why didn’t he alter that?”
“Because he’s a clever devil. For one thing, the Inspector had been in the library, and might possibly have noticed it already. And for another—” Antony hesitated.
“What?” said Bill, after waiting for him to go on.
“It’s only guesswork. But I fancy that Cayley was thoroughly upset about the key business. He suddenly realized that he had been careless, and he hadn’t got time to think it all over. So he didn’t want to commit himself definitely to the statement that the key was either outside or inside. He wanted to leave it vague. It was safest that way.”
“I see,” said Bill slowly.
But his mind was elsewhere. He was wondering suddenly about Cayley. Cayley was just an ordinary man—like himself. Bill had had little jokes with him sometimes; not that Cayley was much of a hand at joking. Bill had helped him to sausages, played tennis with him, borrowed his tobacco, lent him a putter … and here was Antony saying that he was—what? Well, not an ordinary man, anyway. A man with a secret. Perhaps a—a murderer. No, not a murderer; not Cayley. That was rot, anyway. Why, they had played tennis together.
“Now then, Watson,” said Antony suddenly. “It’s time you said something.”
“I say, Tony, do you really mean it?”
“Mean what?”
“About Cayley.”
“I mean what I said, Bill. No more.”
“Well, what does it amount to?”
“Simply that Robert Ablett died in the office this afternoon, and that Cayley knows exactly how he died. That’s all. It doesn’t follow that Cayley killed him.”
“No. No, of course it doesn’t.” Bill gave a sigh of relief. “He’s just shielding Mark, what?”
“I wonder.”
“Well, isn’t that the simplest explanation?”
“It’s the simplest if you’re a friend of Cayley and want to let him down lightly. But then I’m not, you see.”
“Why isn’t it simple, anyhow?”
“Well, let’s have the explanation then, and I’ll undertake to give you a simpler one afterwards. Go on. Only remember—the key is on the outside of the door to start with.”
“Yes; well, I don’t mind that. Mark goes in to see his brother, and they quarrel and all the rest of it, just as Cayley was saying. Cayley hears the shot, and in order to give Mark time to get away, locks the door, puts the key in his pocket and pretends that Mark has locked the door, and that he can’t get in. How’s that?”
“Hopeless, Watson, hopeless.”
“Why?”
“How does Cayley know that it is Mark who has shot Robert, and not the other way round?”
“Oh!” said Bill, rather upset. “Yes.” He thought for a moment, “All right. Say that Cayley has gone into the room first, and seen Robert on the ground.”
“Well?”
“Well, there you are.”
“And what does he say to Mark? That it’s a fine afternoon; and could he lend him a pocket-handkerchief? Or does he ask him what’s happened?”
“Well, of course, I suppose he asks what happened,” said Bill reluctantly.
“And what does Mark say?”
“Explains that the revolver went off accidentally during a struggle.”
“Whereupon Cayley shields him by—by doing what, Bill? Encouraging him to do the damn silliest thing that any man could possibly do—confess his guilt by running away!”
“No, that’s rather hopeless, isn’t it?” Bill thought again. “Well,” he said reluctantly, “suppose Mark confessed that he’d murdered his brother?”
“That’s better, Bill. Don’t be afraid of getting away from the accident idea. Well then, your new theory is this. Mark confesses to Cayley that he shot Robert on purpose, and Cayley decides, even at the risk of committing perjury, and getting into trouble himself, to help Mark to escape. Is that right?”
Bill nodded.
“Well then, I want to ask you two questions. First, is it possible, as I said before dinner, that any man would commit such an idiotic murder—a murder that puts the rope so very tightly round his neck? Secondly, if Cayley is prepared to perjure himself for Mark (as he has to, anyway, now), wouldn’t it be simpler for him to say that he was in the office all the time, and that Robert’s death was accidental?”
Bill considered this carefully, and then nodded slowly again.
“Yes, my simple explanation is a washout,” he said. “Now let’s have yours.”
Antony did not answer him. He had begun to think about something quite different.
IX
Possibilities of a Croquet Set
“What’s the matter?” said Bill sharply.
Antony looked round at him with raised eyebrows.
“You’ve thought of something suddenly,” said Bill. “What is it?”
Antony laughed.
“My dear Watson,” he said, “you aren’t supposed to be as clever as this.”
“Oh, you can’t take me in!”
“No. … Well, I was wondering about this ghost of yours, Bill. It seems to me—”
“Oh, that!” Bill was profoundly disappointed. “What on earth has the ghost got to do with it?”
“I don’t know,” said Antony apologetically. “I don’t know what anything has got to do with it. I was just wondering. You shouldn’t have brought me here if you hadn’t wanted me to think about the ghost. This is where she appeared, isn’t it?”
“Yes.” Bill was distinctly short about it.
“How?”
“What?”
“I said, ‘How?’ ”
“How? How do ghosts appear? I don’t know. They just appear.”
“Over four or five hundred yards of open
