Delbert Cornish pleaded guilty to the first-degree murder of his daughter Hope 'Onyx' Cornish on August 18, 2025 and assault with intent to kill and animal cruelty. He also shot and killed his daughter's pet cat during the same incident. Later he threatened his teenage son, Lucian, who managed to wrestle the gun away and flee the home to call for help. Delbert told a detective that he struggles with depression and was tired of living with his brother, who allegedly bullied his children. Delbert explained to the detective that he wanted to take his own life and the lives of his children because he believed 'they would not be able to carry on in life without him'. First-degree murder in Idaho carries a mandatory sentence of life in prison without the possibility of parole.