"Sure, I can keep up, all right." He reached out and caught her bridle rein, pulling her pony down to a walk in spite of her protests. "I want to show you something. You can't see it riding like a jockey. Look here!" He handed her the shell. "You see, if I had come when you wanted me to, I wouldn't have found it. That's what's called the detective instinct, I reckon," he added, with a grin. "Guess I'm some little Sherlock, after all." "Whose is it?" She turned the shell over in her palm a trifle gingerly. "Look!" He took it from her and pointed out where it had been dented by the firing-pin. "I reckon you wouldn't know, not being up in fire-arms. The hammer that struck this shell didn't hit true; not so far off as to miss fire, you understand, but it ain't in line exactly. That tells me a lot." "What does it tell you?" She looked up at him quickly. "Well," he spoke slowly, "there ain't but one gun in Crawling Water that has that peculiarity, that I know of, and that one belongs, or did belong, to Tug Bailey." She caught at his arm impulsively so that both horses were brought to a standstill. "Then _he_ shot Jensen, Lem?" Her voice was tremulous with eagerness, for although she had never doubted Wade or Santry; had never thought for a moment that either man could have committed the crime, or have planned it, she wanted them cleared of the doubt in the eyes of the world. Her disappointment was acute when she saw that Trowbridge did not deem the shell to be convincing proof of Bailey's guilt. "Don't go too fast now, Dorothy," he cautioned. "This shell proves that Bailey's gun was fired, but it doesn't prove that Bailey's finger pulled the trigger, or that the gun was aimed at Jensen. Bailey might have loaned the rifle to somebody, or he might have fired at a snake, like I did a few minutes ago." "Oh, he might have done anything, of course. But the shell is some evidence, isn't it? It casts the doubt on Tug Bailey, doesn't it?" "Yes, it does that, all right. It casts it further than him." The cattleman spoke positively. "It's a clew, that's what it is. We've got a clew and we've got a motive, and we didn't have either of them yesterday." "How do you suppose that shell got where you found it?" she asked, her voice full of hope. "Bailey must have levered it out of his rifle, after the shooting, and it fell into that hole. You see,"--he could not resist making the triumphant point once more,--"if I hadn't stopped to look for another rattler, I never would have found it. Just that chance--just a little chance like that--throws the biggest criminals. Funny, ain't it?" But she was too preoccupied with the importance of the discovery to dwell on his gifts as a sleuth. "What can we do about it, Lem?" She gave her pony her head and they began to move slowly. "What ought we to do?"