Additional security precautions are being put in place.
Cleveland Elementary School went on lock down to find a gun on campus Friday morning.
School district police said a group of young students told authorities they knew of a "big kid" who brought a gun to school. Police started searching 8th grade classes, where they found a plastic air pellet gun in a student's backpack; later, police searched 7th grade classes, where they found even more weapons.
"They went through our backpacks and they found a kid with two knives he was sitting on," 7th grade student Lucia Gomez said.
Just two weeks ago, a real gun was brought into Van Buren Elementary School by two 7th grade students. Stockton school district police said if children are going to be arming themselves, they're going to take stronger steps to keep those weapons out; starting with bringing in more metal detectors.
Every gun in the hands of a child must first pass through the hands of an adult.