A detective with the Los Angeles County Sheriff's Department was fatally hit by a car Sunday after she helped a pedestrian cross the street, authorities said.

Detective Amber Leist was not on duty at the time of the accident. She was driving past the intersection of Whitsett Avenue and Riverside Drive around 2:00 p.m. EST when she noticed a pedestrian fall while trying to go across the road. Leist rushed to help the person and was hit by a vehicle while returning to her own vehicle, Sheriff Alex Villanueva, said in a press conference Sunday.

The driver of the car reportedly got down to help Leist. She was taken to a hospital where she was pronounced dead.

Leist was a 12-years veteran of the department. She joined as a school resource officer before becoming a patrol officer, and finally being promoted to a detective.

Personnel from the West Hollywood station were replaced by personnel from other locations in order to give them a chance to mourn her loss. The department also reportedly assigned a psychologist to the station.

"This is a sad day for us," Villanueva said. "She was an outstanding detective who would lead by example."

Leist is survived by her two sons, aged 17 and 20. The latter is working with the navy.

Officers from the Valley Traffic Division reached the scene and probed into the matter. Marc Reina, commander of Los Angeles Police Department, said it will take some time to determine who was at fault, according to KCAL 9.

Legal proceedings for Leist took place Sunday night. Her body was transported from Cedars Sinai Hospital to the Los Angeles County Coroner's Office, CNN reported.

accident scene
A police officer is pictured inspecting an accident in Toronto, Ontario on April 23, 2018. Lars Hagberg/AFP/Getty Images