By Rory Carroll

SAN FRANCISCO (Reuters) - The bodies of two males and two females were discovered after firefighters put out a blaze at a mobile home in Modesto, California, police said on Wednesday.

A neighbor told Fox 40 news channel that he heard a big explosion and ran out to find the mobile home, where an elderly couple lived with their grandkids, a six-year-old boy and a ten-year-old girl, engulfed in flames.

Ceres and Westport Fire departments were called to attend the fire south of the center of Modesto, 92 miles (148 km) east of San Francisco, at around 11 p.m. local time on Tuesday.

The ages and identification of the bodies were pending an autopsy scheduled for Monday, said Anthony Bejaran, a spokesman for the Stanislaus County Sheriff's Department.

The autopsy will also establish the cause of death, which will be investigated by detectives, while a fire investigator will try to determine the cause and origin of the blaze, Bejaran said.

(Reporting by Rory Carroll; Editing by Bill Rigby & Simon Cameron-Moore)