"What time?"
The Sergeant answered with a touch of impatience: "Why, between Mrs. North's leaving and Ichabod's arrival, Chief!"
"Less time than that," corrected Hannasyde. "The murder must have been committed after 10.01 and before 10.02."
"Well, if that's so there hasn't been a murder," said the Sergeant despairingly. "It isn't possible."
"But there has been a murder. Two of them."
The Sergeant scratched his chin. "It's my belief Carpenter didn't see it done. If he left at 10.02, he couldn't have. Stands to reason."
"Then why was he killed too?"
"That's what I haven't worked out yet," admitted the Sergeant. "But it seems to me as though he knew something which would have told him who must have committed the murder. Wonder if Angela Angel had any other boy-friends?" He paused, his intelligent eyes more bird-like than ever. "Suppose he was shown out at 9.58? And suppose, when he was walking off, he caught sight of a chap he knew, sneaking in at that side gate? Think that might put ideas into his head? Seems to me he'd add two and two together and make 'em four when he read about the late Ernie's being found with his head bashed in."
"Yes, quite reasonable except for one detail you've forgotten. You're assuming that the man Glass saw at 10.02 was not Carpenter, but the murderer, and we're agreed that whenever that man may have entered the garden he cannot have murdered Fletcher until after 10.01. And that won't do."
"Nor it will," said the Sergeant, discomfited. After a moment's thought, he perked up again. "All right! Say Carpenter went back, to see what this other chap was up to. He saw the murder done, and he legged it for the gate as hard as he could."