San Francisco police are searching for a man suspected of throwing a flammable liquid at his ex-girlfriend and severely burning her.
Officer Carlos Manfredi said witnesses in the city's Bayview District reported hearing the woman screaming a little after noon Sunday.
She was taken to a hospital burn unit with life-threatening injuries.
Investigators believe her attacker was 22-year-old Dexter Oliver.
Manfredi said Oliver had a dated the woman, believed to be in her 20s, but he did not know the circumstances that led to the attack.
He said investigators have not determined the type of liquid thrown at the woman.