The shooting was reported just after 2 p.m. in the 800 block of Lagoon Avenue of the neighborhood near the harbor.
Firefighters and Los Angeles Police Department units responded. Three patients were transported to local hospitals.
Police later said one of the victims, a woman in her 20s, died at the hospital. The other victims, believed to be a man around 20 and a woman around 45, were hospitalized in stable condition.
From aerial footage, it appears an outdoor social gathering was being held at a home near the scene of the shooting.
Information about the circumstances of the shooting was not immediately available. Police believe there were two male suspects involved but there was not a detailed description available.