His thoughts were concentrated on Murphy.

He knew that the fellow was a stubborn, silent, sullen savage, devoid of physical fear, yet cunning, wary, malignant, and treacherous.

That was what they said of him back in Cheyenne.

What, then, would ever induce such a man to open his mouth in confession of a long-hidden crime?
To be sure, he might easily kill the fellow, but he would probably die, like a wild beast, without uttering a word.
There was one chance, a faint hope, that behind his gruff, uncouth exterior this Murphy possessed a conscience not altogether dead.

Over some natures, and not infrequently to those which seem outwardly the coarsest, superstition wields a power the normal mind can scarcely comprehend.