Wednesday a box containing .50 caliber ammunition somehow ended up on the grounds of Lowell Elementary in Sioux Falls after being delivered to a nearby house. A custodian found it and all the shells were accounted for well before students showed up so the school day went on as normal.

District officials tell KSFY they don't know exactly what kind of .50 caliber shells they were. The box was stolen from a house where it had been delivered.

Mother Deb Cline says she got a recorded call from the school about 2 o'clock. "It was scary to think that that kind of stuff can just be laying around. At least it was just ammunition. But it could have been a gun and what if the kids got their before the janitor saw it."

The Sioux Falls School District's Dr. Bill Smith says it's not clear if the box was labeled as ammunition. "My understanding it was dumped near the dumpster and there were a few shells they needed to look for."

All of this happened before 7:15 Wednesday morning. When they got home, Deb says her kids, Kaeman in 4th grade and Enoch in kindergarten, didn't know anything about it. She wishes school officials had told students what happened.

Most of all Deb says as well as the situation ended, it could have been much worse. "But what if it was an older kid and they had guns at their homes, you know you never know. It was scary for me."

Firearms experts tell KSFY these are not common shells. The shells themselves cost about 5 dollars each. And the guns that fire each of them are very expensive as well.