Delbert Cornish, 51, was sentenced to life in prison for the killing of 18-year-old Hope "Onyx" Cornish and his other crimes, Canyon County court records reviewed by Law&Crime show. Thompson dated Delbert Cornish for years and built a family with him, reportedly saying in court that she trusted him and never imagined he would hurt her children. And on that August 2025 day, as the hours passed after the shooting, Delbert Cornish waited for his youngest son, 15-year-old Lucian Cornish, to come home from school. When the teen arrived, Delbert Cornish asked him how school was before telling him "he had killed his sister." It included statements such as "I'm a man of my word my kids died by my hand.