The victim has been identified as Fairfield resident Naomy Rojas. She died of an apparent gunshot wound at the scene, according to police.
The Fairfield Police Department responded to a reported shooting in the 1400 block of Phoenix Drive at about 4:15 a.m. on Saturday, police said.
Upon arrival, officers found Rojas near the railroad tracks located behind the south fence of an apartment complex at 1427 Phoenix Drive, officers said.
No suspect information has been released and the investigation into the homicide is ongoing, police said.
Investigators are attempting to locate witnesses who may have been present during the shooting and are urging anyone with information regarding this crime to call the Fairfield Police Department Major Crimes Unit at (707) 428-7600, the 24-hour Tip Line at (707) 428-7345 or Crime Stoppers at (707) 644-7867. Callers can remain anonymous.