CALDWELL, ID – A Caldwell man faces charges of first-degree murder and aggravated assault after authorities allege he fatally shot his teenage daughter and attacked his son in what police describe as a brutal incident of family violence.
Delbert Cornish, 51, was taken into custody Monday after officers arrived at a residence on Blaine Street and discovered the body of his 18-year-old daughter, Hope Cornish, according to court documents. He is currently being held in Canyon County Jail without bond, pending a preliminary hearing scheduled for September 3.
Investigators say Cornish had been contemplating violence against his family for nearly a year, following the purchase of a 9 mm Hi-Point handgun in the fall of 2023. The details emerged from an interview and probable cause affidavit, which outlined his intentions and actions on the day of the crime.
According to statements provided to police, Cornish consumed several shots of alcohol on Monday morning before entering his daughter’s bedroom and shooting her in the head. The affidavit notes that after the shooting, Cornish kissed his daughter on the cheek and shot her pet cat, later explaining to police that he believed nobody would be able to care for the animal if they died.
Hope Cornish’s body was reportedly covered with a large pride flag, a gesture the suspect told police was meant to honor her, as it held special significance for her.
The situation escalated later that day when Cornish’s son—believed to be 14 or 15 years old—arrived home from school. Cornish informed his son of his sister’s death and attempted to draw him into the bedroom, but the teen refused. When he tried to leave, Cornish allegedly blocked the door and brandished the firearm, at one point firing a round into the ground, police said.
A physical struggle ensued, during which the teenager wrestled the gun away from his father and fled to call 911. Responding officers arrived at the scene later that afternoon, finding evidence throughout the home, including a handgun without a magazine on the living room couch and a note apparently written by Cornish on the wall between the kitchen and living room.
The note indicated Cornish’s intention to kill himself and his children, citing feelings of hopelessness and frustration over his children being bullied, according to investigators.
Police discovered Hope Cornish’s body in a bedroom, with a hatchet embedded in the exterior of the bedroom door. The suspect was not at the scene, prompting authorities to search for his vehicle, a 2020 orange Dodge Challenger registered to his brother. Using license plate reader technology, law enforcement tracked Cornish to Mountain Home, where he was apprehended without incident.
During questioning, Cornish reportedly admitted to shooting his daughter and expressed regret, stating that he struggled with alcoholism and depression. He told investigators he had grown despondent about his life and believed his children would be unable to cope if left without him, the affidavit shows.
Cornish further described long-standing familial tensions, including conflicts with his brother—the children’s guardian—whom he accused of belittling him and his children. He also described his failed plan to kill all three of his children and himself, noting that his eldest son, 24 or 25, was now in prison, disrupting those intentions.
While Cornish initially denied attempting suicide after the attack, he later told officers he tried to end his life with the handgun but was unable to fire the weapon.
Authorities continue to investigate the circumstances surrounding the violence. Cornish remains in custody, and it is unclear whether he has an attorney.