"Could you have seen the man if he had come through the bedroom window?"
"I couldn't have helped seeing him."
"Come, come, sir," said the policeman, with some irritation, "better let me ask the questions. Stands to reason the fellow wouldn't get in through the bedroom window in full view of the street."
"How clever of you to think of that," said Wimsey. "Of course not. Never occurred to me. Then it must have been this window, as you say."
"And, what's more, here's his marks on the window-sill," said the constable triumphantly, pointing to some blurred traces among the London soot. "That's right. Down he goes by that drain-pipe, over the glass roof down there—what's that the roof of?"
"My laboratory," said the doctor. "Heavens! to think that while we were there at dinner this murdering villain——"
"Quite so, sir," agreed the constable. "Well, he'd get away over the wall into the court be'ind. 'E'll 'ave been seen there, no fear; you needn't anticipate much trouble in layin' 'ands on 'im, sir. I'll go round there in 'arf a tick. Now then, sir"—turning to Brotherton—"'ave you any idea wot this party might have looked like?"
Brotherton lifted a wild face, and the doctor interposed.
"I think you ought to know, constable," he said, "that there was—well, not a murderous attack, but what might have been one, made on this woman before—about eight weeks ago—by a man named Marincetti—an Italian waiter—with a knife."
"Ah!" The policeman licked his pencil eagerly. "Do you know this party as 'as been mentioned?" he enquired of Brotherton.