A 13-year-old boy was arrested after bringing a loaded handgun in his backpack to a Southern California middle school, authorities said.
A safety-intervention officer found the weapon Monday after the student was detained and searched at Kolb Middle School in Rialto, said Syeda Jafri, a spokeswoman for with the Rialto Unified School District.
Jafri declined to say how the officer was made aware of the firearm.
Police were notified and the student was taken into custody. He was booked at juvenile hall on suspicion of possession of a firearm in a gun-free school zone and possession of a concealed firearm, the Rialto Police Department said in a news release.
Kolb Middle School Principal Armando Urteaga advised the school staff about the incident and sent a voice message to parents, Jafri said.
Why the student was carrying a loaded gun at school was not immediately clear.
Police and the school district are investigating.