An Idaho father broke down in court as he admitted to killing his daughter and her pet cat. Delbert Cornish appeared in a Canyon County courtroom on November 12, 2025, where he pleaded guilty to first-degree murder for shooting his daughter, Hope “Onyx” Cornish, on August 18, 2025. He also pleaded guilty to assault with intent to kill and animal cruelty.
The hearing was extremely difficult for everyone who loved Onyx. Prosecutors said Cornish shot and killed both his daughter and her cat with a 9-millimeter handgun. After that, he threatened his teenage son, Lucian, who was able to get the gun away from his father and run out of the house to get help.
According to Court TV, when the judge asked Cornish what he did that day, he gave a clear answer through his tears. “I pulled the trigger. I shot my daughter,” Cornish told the court. The judge then asked him if he knew what he was doing when he fired the gun, and Cornish said, “Yes.” His words made the terrible reality of what happened impossible to ignore.
The pain this caused goes far beyond that awful day
Lucian showed incredible bravery when he fought his father for the gun and got away to call for help. His quick thinking probably saved his life. But now he has to live with the memory of that night and the loss of his sister.
Crystal Thompson, Onyx’s mother, said hearing Cornish say those words out loud was almost too much to bear. She compared it to getting hit by a truck. “That was hard. That answer was really – I don’t know. It’s like a truck hit me, just to hear him say it,” Thompson said. “It’s made it all the more real, and I’m really struggling right now with that.”
In Idaho, anyone found guilty of first-degree murder gets life in prison with no chance of getting out.The judge set the sentencing date for January 28, 2026, and plans to allow four hours for people to share how Cornish’s actions hurt them. Family members and others affected by the crime will be able to speak about what they have been through.
Lucian has been trying to deal with his pain by writing music. Thompson said her son wrote a song and is now working on a full album about his feelings.
“He wrote a song, actually, and he’s writing an album… it’s so emotionally raw,” she said. When the sentencing happens, Lucian wants to stand up in court and tell everyone how losing his sister and what his father did has changed his life forever.
Published: Nov 13, 2025 11:15 pm