On December 10th, 2024, Delbert Cornish walked into a sporting goods store in Nampa, Idaho and bought a 9mm handgun. He had a plan. Kill his three teenage children—Onyx, Lucian, and Ian. Then kill himself.

For eight months, Delbert thought about it. Different methods. Different times. On August 18th, 2025, he decided today was the day.

That morning, 18-year-old Onyx Cornish was asleep in her bedroom after working a late shift at Wendy's in Caldwell. Delbert picked up the gun and walked toward her room. As he approached, Onyx opened the door. Surprised to see her father standing there with a weapon.

Delbert raised the gun. Shot Onyx through the top of her head. She fell backward into her room.

Then he sat down. And for the next 20 minutes, Delbert Cornish watched his daughter Onyx gasp for breath. Never called for help. Never tried to save her. Just watched her die.

When it was over, he shot her cat Sammy. Took a hatchet to Onyx's bedroom. Covered her body in a Pride flag. And waited for his 15-year-old son Lucian Cornish to come home from school so he could kill him too.

But Lucian fought back. At 15 years old, he stared down the barrel of his father's gun and refused to die. Lucian disarmed Delbert, escaped, and called 911.

Delbert Cornish sat in court nearly a year later and apologized. Said he supported Onyx's queer identity with an open heart. Said once he saw Lucian's eyes, he couldn't follow through. The judge wasn't buying it.

Before sentencing, Judge Brian Lee did something unusual. He toured Idaho's maximum security prison alone. Walked every cell. Saw where he was sending Delbert Cornish. Then he came back and sentenced him to die there.

"The acts you committed were nothing less than pure evil," Judge Lee told Delbert.

Onyx Cornish's family wore shirts with the number 3—her favorite number. Her mother Crystal Thompson said Onyx was a light in the world. Bold, fearless, full of life. And Delbert destroyed that.

Lucian Cornish survived, but he lives with trauma. Visions of his father Delbert pulling the trigger. He listens to music with one headphone off because he thinks he still hears his dad's voice.

On January 28th, 2026, justice was served. Delbert Cornish received fixed life. No parole. Die in prison. But no sentence brings Onyx Cornish back.

⚠️ This video contains discussion of violence, child death, and trauma. Viewer discretion is advised.

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