His sister, Georgia, and her husband, John Thomas Coop, accepted the boy onto their farm at Plum Creek near Gatesville. The 1880 census records him as being nineteen years old, living in Coryell County, Texas, with his siblings and widowed mother. On July 30, 1884, Miller shot and killed his brother-in-law (with whom he had had an argument) with a shotgun while the latter was sleeping on his porch. Miller was arrested for the murder, convicted, and sentenced to life in prison. The conviction, however, was overturned on a technicality.