Authorities responded to a house on the 4200 block of Arica Avenue at about 8 p.m. and found the bodies of a man and woman. According to Lt. Mike Rosson of the L.A. County Sheriff's Department, the bodies suffered stab wounds.
Police were at the scene for several hours investigating the deaths, and the bodies were removed from the home early Tuesday morning.
The couple lived with their adult son, and according to neighbors, his teenage daughter also moved in a few years ago.
Several neighbors said they had known the couple for many years.
"It's just shocking. They were nice people, I've known them all my life," said neighbor Gary Rios.
The victims' son was detained by investigators for questioning, Rosson said they are not yet saying he is a person of interest.
Anyone with information is urged to call the L.A. County Sheriff's Homicide Bureau at (323) 890-5500.