"Signs o' torment. But what? Somethin's on your mind. Quick, what is it?"
"Well, it must have been a damned fool of a burglar," said Antrim. "Why did he get in by that window? There's a French window in the surgery, with a flimsy catch that wouldn't stand up for a second. It'd be easy — walk right in like a door. Instead, this fellow takes a sash-window rather high up from the ground, and a window that sticks, and a window that's generally inconvenient. The French window doesn't seem to have been touched. Why?"
Again we all expected H.M. to attack in the obvious fashion, and pull Antrim's moonlight intruder to pieces. And again, as in Mrs. Antrim's case, he never touched the obvious. I looked at Charters, and then at Evelyn, and none of us could understand what sort of lopsided game H.M. was playing. It was not long before its terrible purpose became clear to us. But I have later heard the Commissioner of the Metropolitan Police (a dignitary known to H.M. as Boko) say that the truth was never more subtly hidden under the obvious than in this case, which began as a high adventure and ended as a psychological puzzle at dawn.
At the moment H.M. sat prodding absently at the eyes of the skull with the stem of his pipe.
"Then that's all clear. Siddown, son," he said to Antrim. "I told you I was goin' to relieve you of responsibility. I want to take you over some quick hurdles now, and I don't want you to miss any of 'em. First, they tell me you knew Paul Hogenauer pretty well. Ever go to his house in Moreton Abbot?"
"Yes. I mean, once or twice."
"Where'd he entertain you? What room?"
"The back parlour. His study. I know," Antrim rapped out quickly, "you're going to ask me about his `studies.' I didn't know. I still don't! That's what worried me still more. He'd let drop all sorts of cloudy hints. `Walking unseen.' Bah." Antrim gave what can only be described as a heavy and genial sneer. "If you know so much about it, I wish you'd tell me."
"Easy, son. I wasn't goin' to ask you that. But you knew he always kept the shutters closed on that room?"
Antrim was interested. "Oh, yes. But he had a good explanation for that. Said it wasn't at all a queer trick. He said that he sometimes did experiments in there, and he had to close the shutters for 'em. He said he didn't want the neighbours to grow curious. So, he said, if he kept the shutters closed all the time they'd get used to it and wouldn't think anything of it. Great hand at being respectable, Hogenauer was. Anxious to keep on the good side of everybody — neighbours — police — everyone. Or so it seemed."