"There aren't any rocks."
"No. Good man. But there are the equivalent. There are stone groins."
"Yes. Yes, so there are! Think that was how it was done, sir?"
"Who knows? It's a theory. But the coat still worries me."
"I don't see why it need, sir. It was a misty morning, a bit chilly at six. Anyone might have worn a coat."
"Y-es," Grant said doubtfully, and let the matter drop, this being one of those unreasonable things which occasionally worried his otherwise logical mind (and had more than once been the means of bringing success to his efforts when his logic failed).
He gave Williams instructions for his further inquiries, when he himself should be in town. "I've just had another few minutes with Tisdall," he finished. "He has got himself a waiter's job at the Marine. I don't think he'll bolt, but you'd better plant a man. Sanger will do. That's Tisdall's car route on Thursday morning, according to himself." He handed a paper to the sergeant. "Check up on it. It was very early but someone may remember him. Did he wear a coat or not? That's the main thing. I think, myself, there's no doubt of his taking the car as he said. Though not for the reason he gave."
"I thought it a silly reason myself, when I read that statement. I just thought: 'Well, he might have made up a better one! What's your theory, sir?"
"I think that when he had drowned her his one idea was to get away. With a car he could be at the other end of England, or out of the country, before they found her body! He drove away. And then something made him realize what a fool he was. Perhaps he missed the button from his cuff. Anyhow, he realized that he had only to stay where he was and look innocent. He got rid of the telltale coat — even if he hadn't missed the button the sleeve almost up to the elbow must have been soaking with salt water — came back to replace the car, found that the body had been discovered thanks to an incoming tide, and put on a very good act on the beach. It wouldn't have been difficult. The very thought of how nearly he had made a fool of himself would have been enough to make him burst into tears."
"So you think he did it?"