Irene Gonzalez was shot in the early hours of September 15 in the 12500 block of Oak Street.
Investigators said the mother of two was soliciting services as a sex worker when she entered a black Toyota Corolla with tinted windows and a sunroof.
The sheriff's department said video shows the Corolla traveling along Long Beach Boulevard before turning west on Euclid Avenue and then heading on Oak Street, where it stopped mid-block.
Gonzalez got out of the vehicle and was allegedly shot by the driver moments before collapsing on the sidewalk, where she was pronounced dead, authorities said.
The relationship between Gonzalez and the suspect, if any, was unclear. A motive for the shooting has not been determined.
"She left two kids behind, and somebody cruel just took her away from them," said Gonzalez's friend Gladys Rodriguez. "They need her. They need her here with us."
The Los Angeles County Board of Supervisors is offering the reward for any information leading to the identification, arrest, and conviction of the suspect.
Anyone with information regarding the deadly shooting was urged to call the Sheriff's Homicide Bureau at 323-890-5500. Tipsters who prefer to remain anonymous can call Crime Stoppers at 800-222-8477 or visit lacrimestoppers.org.
City News Service, Inc. contributed to this report.