‘Senseless, cruel, cowardly, and callous’: Man sentenced to life for murdering his teen daughter and her cat

CALDWELL, Idaho (TCN) -- A man has been sentenced to life in prison without the possibility of parole for the murder of his 18-year-old daughter and the attempted murder of his 15-year-old son.

In a statement, the Canyon County Prosecuting Attorney’s Office said 51-year-old Delbert Cornish was charged with first-degree murder and attempted murder. He was also charged with animal cruelty in connection with fatally shooting his daughter’s pet cat. 

KTVB reports that in exchange for not facing the death penalty, Cornish pleaded guilty to the charges of first-degree murder, assault with intent to commit murder, cruelty to animals, and use of a deadly weapon in the commission of a felony in November 2025.

Law & Crime reports that on Aug. 18, 2025, Cornish reportedly took several shots of alcohol, went into the bedroom of his daughter, Hope “Onyx” Cornish, and shot her in the head. He then reportedly kissed her cheek, shot her pet cat, and covered his daughter’s body with a Pride flag to honor her, according to a probable cause affidavit obtained by the outlet. He then waited for his son, 15-year-old Lucian Cornish, to come home from school.

When his son arrived, Law & Crime reports Cornish told him he had killed his sister and urged him to go check on her, but Lucian Cornish reportedly refused. Delbert Cornish then fired a gun at the ground and his son reportedly wrestled the gun away and called 911, according to the outlet.

Responding officers found an apparent suicide note on the wall saying, ”I’m a man of my word my kids died by my hand. I’m tired of them being made fun of” and “I’m going! My kids are going with me,” Law & Crime reports.

Authorities apprehended Cornish about 70 miles from the home. He reportedly told them, “I’m not gonna lie. I did it, dude.”

Cornish had purchased a gun about a year prior and reportedly been planning to kill his children and himself ever since, Law & Crime reports.

In court, Cornish apologized, Idaho 6 News reports. He said, “I could never muster enough words to convey the amount of regret, anguish and remorse I have for what I’ve done to each and every one, including those that never had a chance to meet her… That’s a debt I could never pay back in this lifetime or the next.”

At the end of the sentencing, Third District Judge Gabriel McCarthy told the court, “If there’s a God, perhaps God will have mercy on his soul. But the state of Idaho does not,” according to the prosecuting attorney’s office.

The Idaho Statesman reports Cornish will be transferred from jail to state prison to begin serving his life sentence.

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