Investigators were looking into a fire at the Smith Correctional Facility in Banning Thursday morning.
The fire broke out Wednesday at 10:40 p.m. inside the Riverside County Jail facility on the 1600 block of Hargrave Street.
Riverside County Sheriff's Deputies said the fire started in an unoccupied building and flames were visible.
Crews were on the scene until at least 2:00 a.m. Thursday morning.
No inmates were affected. They remained secured in their cells Thursday morning.
Stay with KESQ News Channel 3 for updates.