“Everything!” returned Roger largely. “Our interview just now; my idea about Mrs. Russell; your suspicions of Miss Cross (if you really have suspicions, and aren’t just pulling my leg)—everything!”
“Very well, sir,” said the inspector equably. “Where shall we start?”
“Well, we began just now with Miss Cross. I want to add a word to the very dogmatic statement I made, though it’s not really necessary. You know, of course, why I’m so convinced she had nothing to do with it?”
“Well, I won’t make you wild by saying ‘because she’s an uncommonly pretty girl,’ ” the inspector smiled. “I’ll wrap it up a bit more and say ‘because you think she couldn’t commit a murder to save her life.’ ”
“That’s right,” Roger nodded. “In other words, for overwhelmingly psychological reasons. If that girl isn’t as transparently straight as they make ’em, may I never call myself a judge of character again!”
“She is uncommonly pretty, I must say,” remarked the inspector non-committally.
Roger disregarded the irrelevance. “You must have to make use of psychology in your business, Inspector, and continual use too. Every detective must be a psychologist, whether he knows it or not. Don’t all your instincts tell you that girl’s as innocent—I don’t mean merely of this crime, but innocent-minded—as you’d wish any daughter of your own to be?”
The inspector tugged at his moustache. “We detectives may have to know a bit about psychology, as you say, sir; I’m not disputing that. But it’s our business to deal in facts, not fancies; and the thing we’ve got to pay most attention to is evidence. And in nine cases out of ten I’ll back evidence (even purely circumstantial evidence like this) against all the psychology in the world.”
Roger smiled. “The professional point of view, as opposed to the amateur. Well, naturally I don’t agree with you, and as I said, I’m not at all sure that you aren’t pulling my leg about Miss Cross all the time. Let’s go on to that interview of ours this evening. I needn’t ask you whether you saw that Master Colin wasn’t being altogether as frank with us as he might have been. He was keeping something back, wasn’t he?”
“He was, sir,” the inspector agreed cheerfully. “His real reason for breaking with Mrs. Vane.”