In the quiet town of Caldwell, Idaho, the life of Hope Onyx Cornish, an 18-year-old White/Caucasian female, came to a tragic and violent end on August 18, 2025. Known to her friends and family as Onyx, she was described as a fiery, stylish, and kind individual who had recently overcome struggles with substance abuse and was looking forward to her future. She was working at a local Wendy's and had been sober for over a year, a testament to her strength and determination.
Her life, however, was cut short in an act of violence that stunned the community.
The person responsible for her death was her own father, 51-year-old Delbert Cornish. In the months leading up to the tragedy, Delbert had been battling his own demons, including alcoholism and depression. He later confessed to police that he had been harboring a dark plan for nearly a year to kill his three children and then himself. He felt they were being bullied by his brother, with whom the family lived, and believed they would not be able to go on without him. His eldest son's return to prison on a parole violation had reportedly thwarted his initial plans. On the morning of August 18th, after consuming several shots of alcohol, he decided to carry out his grim resolution.
Delbert went to Onyx's room with a 9mm handgun he had purchased the previous fall. When his daughter unexpectedly opened the door, he shot her in the head. In a chilling confession to investigators, he admitted to watching her gasp for breath for nearly twenty minutes before she died. Afterward, he covered her body with a Pride flag, an act he claimed was meant to "honor her" as it was something that would have been deeply meaningful to her. He also killed her cat. The horror of the day continued when Onyx's teenage brother returned home from school. Delbert calmly told the boy that he had killed his sister. A brief struggle ensued, but the son managed to escape the house unharmed and call 911.
Following the call, police arrived at the family's home on Blaine Street to a horrific scene. They found Onyx deceased inside. Delbert Cornish had already fled, but he was apprehended later that evening about 70 miles away in Mountain Home. During his arrest and subsequent interviews, he confessed to the murder, expressing remorse and stating he should have shot himself as well. He was charged with first-degree murder, assault with intent to commit murder, and animal cruelty. Court documents revealed the depth of his disturbed state of mind and the premeditated nature of the crime. His lawyer later indicated that he intended to plead guilty to the charges brought against him.
