A California school is on lockdown Wednesday afternoon after a dog found a gun in a student's backpack and on him, local radio station KPCC reported.
Police arrested the Mark Keppel High School junior and are searching all the classrooms the student attended, as well as talking to his friends. They are also at his home in Monterey Park, Calif.
The radio station reports that the school district contacted a local canine company to do a random search.
The school is located in Alhambra, Calif.