Detectives said the officer found his 79-year-old mother, Cleo Hughes, shot dead in her South Los Angeles home in the 1600 block of West 66th Street on Sunday.
Family, friends and fellow officers provided comfort to the victim's son, who works at the Los Angeles Police Academy training new recruits.
Investigators said he was with his mother Saturday and dropped her off at her home about 7 p.m. He called her Sunday morning, but she didn't answer the phone. He went to her home to check on her and found her in bed with a gunshot wound to the chest.
Detectives have searched the victim's home and questioned residents in the community looking for clues.
"Any time any citizen of the Los Angeles area or anybody - it doesn't matter if it's a department employee or not - dealing with a senseless murder, the department is going utilize its resources to investigate the situation," said LAPD Officer Cleon Joseph.
Detectives said there were no signs of forced entry at the house.
"It's cowardice," Joseph said. "It's a person who probably did nothing to no one, elderly woman at that, it makes no sense. We just are looking for any leads."
Family and friends of the victim were grief stricken.
"You don't know what's going to happen," said Angela Elegado of South L.A. "You don't know if somebody out there is a murderer."