William "Billy" Smith was a Montana lawman and a Stock Detective in the 1880's. See Huffman photograph book for another photograph of him in a group shot. Stock Detectives were generally armed men who were hired by Cattle Barons, Ranchers, and Vigilante Leaders to hunt down rustlers and thieves. They either ran them off, shot them, or hanged them. I believe he worked in this way for the 1880's Montana Vigilantes, under Ford and Granville Stuart.
