“And look at the deliberation of the fellow. Fancy stopping to collect those bits of vase and cover up the traces of that second shot like that! He must have some nerve. Yes, it certainly looks more and more as if it was a prearranged thing. I don’t say for last night in particular; that may only have been a favourable opportunity which the chap was quick to seize. But I do think that he’d made up his mind to kill Stanworth some time or other.” “You think it was somebody Stanworth knew, then?” “Oh, there’s not much doubt about that. And somebody he was vastly afraid of, too, I should imagine. Why else should he keep a revolver so handy, if he wasn’t expecting something of the kind? Yes, that’s the line we ought to go on—see if we can discover whether there was anybody among his acquaintances of whom Stanworth was thoroughly frightened. If we can only find that out, and the name of the person as well, the odds are ten to one that we shall have solved the mystery of the murderer’s identity.” “That sounds reasonable enough,” said Alec with interest. “Got any theory of how it was done?” Roger beamed. “I believe I can tell you exactly how it was done,” he said, not without pride. “Listen!” He recounted at some length the results of his after-lunch meditations and explained the reasons upon which his conclusions had been based. It took the two of them several circuits of the rose garden before the recital was completed, and then Roger turned expectantly to his companion. “You see?” he concluded eagerly. “That accounts for everything except the facts of the confession and the murderer’s escape from the library. Now I’ve cleared up the confession, and we’ve only got one difficulty to get over. What do you think of it?” “Humph!” observed Alec cautiously. He paused, and it was evident that he was thinking deeply. “Well?” asked Roger impatiently. “There’s one thing I don’t quite see,” Alec said slowly. “According to you the shot that killed Stanworth was fired from the other man’s revolver. Then how is it that the bullet they took out of his head fitted the empty shell in his _own_ revolver?” Roger’s face fell. “Hullo!” he exclaimed. “That never occurred to me.” “I thought it couldn’t have,” said Alec complacently. “That rather knocks your theory on the head, doesn’t it?” “It’s one to you, Watson, certainly,” Roger smiled a little ruefully. “Ah!” observed Alec deeply. He was evidently not going to spoil the impression he had just made by any rash remarks. Alec was one of those fortunate people who know just when to stop. “Still, after all,” Roger said slowly, “that’s only a matter of detail, isn’t it? My version of how it happened may be quite wrong. But that doesn’t affect the main issue, which is that it _was_ done.” “In other words, the fact of murder is definitely established, you think, although you don’t know how it was carried out?” Alec asked thoughtfully. “Precisely.” “Humph! And do you still think the motive was robbery?”