Emergency officials received initial calls of a structure fire in the 31000 block of Industrial Parkway Southwest shortly before 10 p.m. The report was quickly changed from a structure on fire to a person engulfed in flames.
Hayward firefighters and police responded within minutes but the female victim had already sustained to injuries sustained from the fire, police said.
The victim has not been identified.
Police said investigators have not ruled out any cause of death and are speaking with witnesses at the scene.
Anyone with information is asked to call police at (510) 293-7082.