BELLEVUE, Neb. (AP) — Police in the Omaha suburb of Bellevue are investigating after an elementary school employee found a weathered backpack on school grounds full of ammunition.

Bellevue police called on the Omaha Police Department’s bomb squad for help, which X-rayed the bag.

Police say the backpack, which was found Thursday under brush by a fence at Bellaire Elementary School, contained 107 rounds of ammunition. The ammo included .38 caliber, .44 caliber and .308 caliber shotgun shells.

Police say the ammunition appeared to be weathered, and it was unclear how long the bag had been there.