Detectives say a man and a woman were shot as they sat in the front seat of a car in the 11300 block of Medina Court at 12:30 a.m.
The suspect approached the vehicle on foot and fired multiple shots at both victims, according to Los Angeles County Sheriff's Department Deputy Quiana Birkbeck.
Simon Mendoza, 40, of Whittier was pronounced dead at the scene. The female victim was also struck, but suffered only minor injuries.
No other details were released.
The investigation is ongoing. Anyone with information about the case was urged to call sheriff's homicide detectives at (323) 890-5500.