“I thought you would,” said Roger cheerfully. “Of course there were other things that clinched it. The disappearance of that footprint, for instance. That _must_ have been done by somebody who knew what he was doing. And somebody who heard me say that I was going to fit every male boot in the house into the mark, you remember. Of course it was that which made me so sure at first about Jefferson, because I jumped to the conclusion that it must have been Jefferson whom we saw edging out of the library door. After that I more or less had Jefferson on the brain.” “I did my best to put you off that track,” said Alec with a slight smile. “Oh, you did. It wasn’t your fault that I clung to him so persistently.” “I tried hard to stop you putting your foot in it, if you remember.” “I know. And I daresay it’s lucky you did. I might have put things a good deal more plainly to him, with extremely awkward results, if you hadn’t dinned it into me so hard.” “Well,” Alec said slowly, “what are you going to do about it, now you’ve presumably got at the truth at last?” “Do about it? Forget it, of course. I told you my views just now, when I said the man who killed Stanworth ought to be acclaimed as a public benefactor. As that is unfortunately out of the question, the next best thing is to forget as diligently as possible that Stanworth did not after all shoot himself, as everybody else believes.” “Humph!” said Alec, gazing out of the window. “I wonder! You’re really sure of that?” “Absolutely,” said Roger with decision. “Anything else would be ludicrous under the circumstances. We won’t discuss that side of it again.” There was a little pause. “The—the second woman,” Alec said tentatively. “How were you able to identify her so positively?” Roger drew the envelope out of his breast pocket, opened it, and carefully extracted the hair. He laid it across his knee for the moment and contemplated it in silence. Then with a sudden movement he picked it up and threw it through the open window. “There goes a vital piece of evidence,” he said with a smile. “Well, for one thing, there was nobody else in the house with just that particular shade of hair, was there?” “I suppose not,” Alec replied. There was another silence, rather longer this time. Then Roger, glancing curiously across at his companion, remarked very airily: “Just to satisfy my natural curiosity, Alec, why exactly _did_ you kill Stanworth?” Chapter XXVIII What Really Did Happen Alec contemplated the tips of his shoes for a moment. Then he looked up suddenly. “It wasn’t exactly murder, you know,” he said abruptly. “Certainly not,” Roger agreed. “It was a well-merited execution.” “No, I don’t mean that. I mean, if I hadn’t killed Stanworth, he would probably have killed me. It was partly self-defence. I’ll tell you the whole story in a minute.”