He rowed slowly towards the middle of the pond.
"You're about there now," said Bill at last.
Antony stopped rowing and looked about him.
"Yes, that's pretty well right." He turned the boat's nose round until it was pointing to the pine-tree under which Bill had lain. "You see my tree and the other coat?"
"Yes," said Bill.
"Right. Now then, I'm going to row gently along this line until we're dead in between the two. Get it as exact as you can — for your own sake."
"Steady!" said Bill warningly. "Back a little…. a little more…. a little more forward again…. Right." Antony left the oars on the water and looked around. As far as he could tell, they were in an exact line with each pair of landmarks.
"Now then, Bill, in you go."
Bill pulled off his shirt and trousers, and stood up.
"You mustn't dive from the boat, old boy," said Antony hastily. "You'll shift its position. Slide in gently."
Bill slid in from the stern and swam slowly round to Antony.
"What's it like?" said Antony.
"Cold. Well, here's luck to it."
He gave a sudden kick, flashed for a moment in the water, and was gone. Antony steadied the boat, and took another look at his landmarks.
Bill came up behind him with a loud explosion. "It's pretty muddy," he protested.
"Weeds?"
"No, thank the Lord."
"Well, try again."
Bill gave another kick and disappeared. Again Antony coaxed the boat back into position, and again Bill popped up, this time in front of him.
"I feel that if I threw you a sardine," said Antony, with a smile, "you'd catch it in your mouth quite prettily."
"It's awfully easy to be funny from where you are. How much longer have I got to go on doing this?"
Antony looked at his watch.
"About three hours. We must get back before daylight. But be quicker if you can, because it's rather cold for me sitting here."
Bill flicked a handful of water at him and disappeared again. He was under for almost a minute this time, and there was a grin on his face when it was visible again.
"I've got it, but it's devilish hard to get up. I'm not sure that it isn't too heavy for me."
"That's all right," said Antony. He brought out a ball of thick string from his pocket. "Get this through the handle if you can, and then we can both pull."
"Good man." He paddled to the side, took one end of the string and paddled back again. "Now then."
Two minutes later the bag was safely in the boat. Bill clambered in after it, and Antony rowed back. "Well done, Watson," he said quietly, as they landed. He fetched their two coats, and then waited, the bag in his hand, while Bill dried and dressed himself. As soon as the latter was ready, he took his arm and led him into the copse. He put the bag down and felt in his pockets.
"I shall light a pipe before I open it," he said. "What about you?"
"Yes."
With great care they filled and lit their pipes. Bill's hand was a little unsteady. Antony noticed it and gave him a reassuring smile.
"Ready?"
"Yes."
They sat down, and taking the bag between his knees, Antony pressed the catch and opened it.
"Clothes!" said Bill.
Antony pulled out the top garment and shook it out. It was a wet brown flannel coat.
"Do you recognize it?" he asked.
"Mark's brown flannel suit."
"The one he is advertised as having run away in?"
"Yes. It looks like it. Of course he had a dashed lot of clothes."
Antony put his hand in the breast-pocket and took out some letters. He considered them doubtfully for a moment.
"I suppose I'd better read them," he said. "I mean, just to see—" He looked inquiringly at Bill, who nodded. Antony turned on his torch and glanced at them. Bill waited anxiously.
"Yes. Mark…. Hallo!"
"What is it?"
"The letter that Cayley was telling the Inspector about. From Robert. 'Mark, your loving brother is coming to see you—' Yes, I suppose I had better keep this. Well, that's his coat. Let's have out the rest of it." He took the remaining clothes from the bag and spread them out.
"They're all here," said Bill. "Shirt, tie, socks, underclothes, shoes — yes, all of them."
"All that he was wearing yesterday?"
"Yes."
"What do you make of it?"
Bill shook his head, and asked another question.
"Is it what you expected?"
Antony laughed suddenly.
"It's too absurd," he said. "I expected — well, you know what I expected. A body. A body in a suit of clothes. Well, perhaps it would be safer to hide them separately. The body here, and the clothes in the passage, where they would never betray themselves. And now he takes a great deal of trouble to hide the clothes here, and doesn't bother about the body at all." He shook his head. "I'm a bit lost for the moment, Bill, and that's the fact."
"Anything else there?"
Antony felt in the bag.
"Stones and — yes, there's something else." He took it out and held it up. "There we are, Bill."
It was the office key.
"By Jove, you were right."
Antony felt in the bag again, and then turned it gently upside down on the grass. A dozen large stones fell out — and something else. He flashed down his torch.
"Another key," he said.
He put the two keys in his pocket, and sat there for a long time in silence, thinking. Bill was silent, too, not liking to interrupt his thoughts, but at last he said:
"Shall I put these things back?"
Antony looked up with a start.
"What? Oh, yes. No, I'll put them back. You give me a light, will you?"
Very slowly and carefully he put the clothes back in the bag, pausing as he took up each garment, in the certainty, as it seemed to Bill, that it had something to tell him if only he could read it. When the last of them was inside, he still waited there on his knees, thinking.
"That's the lot," said Bill.
Antony nodded at him.
"Yes, that's the lot," he said; "and that's the funny thing about it. You're sure it is the lot?"
"What do you mean?"
"Give me the torch a moment." He took it and flashed it over the ground between them. "Yes, that's the lot. It's funny." He stood up, the bag in his hands. "Now let's find a hiding-place for these, and then—" He said no more, but stepped off through the trees, Bill following him meekly.
As soon as they had got the bag off their hands and were clear of the copse, Antony became more communicative. He took the two keys out of his pocket.
"One of them is the office key, I suppose, and the other is the key of the passage cupboard. So I thought that perhaps we might have a look at the cupboard."
"I say, do you really think it is?"
"Well, I don't see what else it can be."
"But why should he want to throw it away?"
"Because it has now done its work, whatever it was, and he wants to wash his hands of the passage. He'd throw the passage away if he could. I don't think it matters much one way or another, and I don't suppose there's anything to find in the cupboard, but I feel that we must look."
"Do you still think Mark's body might be there?"
"No. And yet where else can it be? Unless I'm hopelessly wrong, and Cayley never killed him at all."
Bill hesitated, wondering if he dare advance his theory.
"I know you'll think me an ass—"
"My dear Bill, I'm such an obvious ass myself that I should be delighted to think you are too."
"Well, then, suppose Mark did kill Robert, and Cayley helped him to escape, just as we thought at first. I know you proved afterwards that it was impossible, but suppose it happened in a way we don't know about and for reasons we don't know about. I mean, there are such a lot of funny things about the whole show that — well, almost anything might have happened."