Chattanooga Police were called to Howard High School on Tuesday morning after "multiple" students were congregated outside the school off campus during school hours.
Officers moved the students back into the school and, while doing so, located a gun in the backpack of one student.
Police said at 10:15 a.m. they were notified of the multiple juveniles outside of the school.
It was while getting ready to transport the students that the firearm was found.
Police confiscated the gun and notified the parents.
The student was arrested.
Police said, "The student never brought the firearm into the school. The SRO and officers found the firearm before being able to do so. The students were found off campus and brought back to school."