Police were called to a home on the 1500 block of G Street at around 7:30 p.m. Saturday to conduct a welfare check on the elderly resident, police reported.
Officers arriving at the scene reported finding the woman dead from multiple stab wounds, and her nephew, Carrel Grayson, in the woman's home with her body.
Grayson, a homeless man sometimes fed by his aunt and allowed to sleep in a neighbor's garage, was detained by investigating officers for questioning at the Antioch Police Department.
While in custody, Grayson admitted to murdering his aunt after forcing his way into her home and assaulting her, all because he was angry and cold, according to police.
Officers had recently been called to the home of Grayson's aunt and arrested him for public drunkenness and burglary, police said.
Antioch police reported that Grayson will be charged with his aunt's murder and transported to the Contra Costa County Jail in Martinez.
