Turlock investigators released how a family of four died in their Red Oak Court home six weeks ago.
Turlock police making a welfare check at the request of relatives on June 26 found parents Sarkis Babakhan, 78, and Rozmary Babakhan, 70, and their sons, Rodney Bowman, 39, and Robert Babakhan, 42, dead.
Turlock fire investigators determined a fire had been deliberately set in the home, said police officer Mayra Lewis. The parents had been stabbed to death, and it was the younger son, Bowman, who had killed them, deputy coroners and a forensic pathologist with the Stanislaus County Coroner's Office concluded.
Bowman died from inhalation of smoke and toxic chemicals produced by the fire.
Robert Babakhan was disabled. He succumbed to smoke and toxic chemical inhalation after the fire burned itself out, the coroners reported.