The incident was reported about 12:15 p.m. in the 700 block of West Route 66, where officers found a woman in a waiting vehicle and took her into custody, Glendora police said in a statement.
A perimeter was established at the scene and a search began for two suspects described by witnesses as being armed with handguns. According to the news release, one of the suspects was shot by police after being located in the area of Route 66 and Forestdale Avenue.
The wounded man was transported to a hospital in unknown condition, authorities said. No officers were hurt.
There is an off campus incident near Stanton Elementary. All students and staff are safe and accounted for. Stanton is on lockdown as a safety precaution.— Glendora Unified (@GlendoraUnified) September 6, 2019
The third suspect remained at large. He is described as black, thin, with short dreadlocks and the sides of his head shaved. He was last seen wearing blue jeans and a black hooded sweatshirt or a white T-shirt.
Nearby Stanton Elementary School and Foothill Christian School were both placed on lockdown as a precaution. A plan was in place to have students transported to a safe area where their parents could pick them up, officials said.
"All students and staff are safe and accounted for," the Glendora Unified School District said in a statement.
Anyone with information about the incident is asked to call the Los Angeles County Sheriff's Department's Homicide Bureau at (323) 890-5500.