A California Highway Patrol cruiser rolled over while pursuing a stolen vehicle on the 91 Freeway Tuesday night. 

The Los Angeles County Sheriff's Department began the chase at roughly 7:30 p.m. near Compton before the Dodge Challenger driver entered the highway. Deputies said the car was initially stolen from the Westlake District area. 

Once the westbound 91 Freeway, the California Highway Patrol joined the pursuit. Shortly after, the officer's cruiser flipped and came to rest on its roof. 

It's unclear what caused the crash. Police have requested an ambulance for the officer. 

The suspect fled after the crash.