Los Angeles police Sgt. Wes Alban said 22-year-old Joe Calderon was arrested Sunday at the Mission Hills home he shared with his grandparents.
Investigators believe Calderon fought with his grandparents Saturday night and, after his grandfather went to work Sunday, continued arguing with his grandmother. They suspect that Calderon beat his grandmother, who called her daughter for help.
Alban said that when the daughter went to the home, she saw blood on Calderon's hands and called police.
Detectives found the grandmother's body in the kitchen and several objects around her that could have been the murder weapon. They include the barbecue fork that appeared to have blood on the prongs.