It happened just before 4 p.m.
Lt. Vincent Ursini with the Los Angeles County Sheriff's Department - who's assisting in the investigation - said two veteran officers with the Azusa Police Department were responding to reports of a stolen vehicle.
He said they had information about a vehicle near Jackson Avenue and Gladstone Street that matched the description.
Ursini said the two officers attempted to approach the suspect in the vehicle, who was described only as a young white male. When officers got close, that's when the suspect took off. Ursini said he pulled out a gun and a "close range shootout" ensued.
The officer was shot and fired back at the suspect, striking him.
He was killed at the scene.
Meanwhile, a woman, who was in the car with the suspect, was taken into custody.
Ursini said the officer was rushed to a nearby trauma center and underwent surgery. He's currently stable and is expected to make a full recovery.
Ursini called this incident "rare" for the Azusa Police Department.
The incident remains under investigation.