STOCKTON (CBS13) – Stockton police responded in force to an elementary school with a tragic past after reports of a weapon on campus Friday morning.

At least nine police units were parked outside Cleveland Elementary School on East Fulton Street after getting calls reporting a gun on the school grounds.

The school was put on lockdown as officers searched the school. After a short time, they found a pellet gun in the backpack of a student.

Police then went classroom to classroom to make sure there were no other weapons on campus.

No students were hurt.

Cleveland Elementary was the scene of a fatal shooting in 1989. Five children died and 29 others were injured when Patrick Purdy opened fire with an AK-47 as students played in the school yard.

The shooting spurred calls nationwide for regulation of semi-automatic weapons.