ESTHERVILLE, Iowa | Authorities are trying to determine who brought ammunition into Estherville Lincoln Central Middle School on Thursday and in December.
Two students found a .22-caliber cartridge in a seventh-grade classroom on Thursday. In December, a .25-caliber cartridge was found in a hallway at the same school.
No one was hurt.
The middle school was on lock down after the cartridge was found Thursday while police and school officials questioned students and searched lockers.
Estherville Lincoln Central Superintendent Tara Paul said officials don't know who brought the ammunition into the school.
Officials also don't know if it was brought in accidentally or on purpose.
In December, the .25-caliber cartridge was found the day after a basketball game.
“That one could have come from anywhere, including adults that could have been in the building the night before,” said Estherville police Capt. Brent Shatto.
School officials are asking parents to check their children's coats and backpacks to make sure children don't bring any contraband into the school.