Shortly after noon, police responded to a report of shots fired in the 300 block of Springs Road.
Arriving officers found White, a Fairfield resident, dead in the backyard of a home at 315 Springs Road, police Lt. Abel Tenorio said.
White and his girlfriend had just returned to her home from a church service in Fairfield when he was killed, police said.
The suspect is described as a black man in his 20s who is between 5 feet 10 inches and 6 feet tall with a medium build. He was wearing a white shirt and blue jeans, according to police.
After the shooting, the suspect was seen getting into the passenger seat of a car described as a white or silver Honda or similar compact car. The vehicle was last seen traveling east on Springs Road toward Tuolumne Street, police said.
No arrests had been made as of early this afternoon, and police are not releasing information about a possible motive for the shooting, which is the city's 11th homicide of the year, Tenorio said.
Anyone with information about the case is asked to contact Detective Mat Mustard or Detective Ted Postolaki of the Police Department's investigation division at (800) 488-9383.