CLEVELAND (WJW) — The FOX 8 I-Team has found a growing mystery behind ammunition for a gun spotted by a second-grade student in a classroom.

The Cleveland Metropolitan School District told us it can’t determine how the ammo got there.

An investigation surrounds the Dike School of the Arts along East 61^st Street in Cleveland.

This week, the district told us a student had found a magazine, or clip, for a weapon in a classroom for second-graders.

Now, the district has released a statement, saying:

“CMSD has concluded its investigation of the incident at Dike School of the Arts. That investigation included interviews with all subjects identified as having had access to the area where the item was found at the start of the school day. Those interviewed included a teacher, a parent, several students, and cleaning staff. Based on those interviews, no suspect has been identified. Students interviewed were referred to 696-KIDS [the Cuyahoga County child abuse hotline] for further investigation.”

This week, we also spoke to Ken Trump, a local man who runs National School Safety and Security Services, a school safety consulting firm.

Nationwide, there have been a number of recent cases involving guns and bullets and the youngest kids at schools, he told us.

“In the last few weeks of this school year, already, we’ve seen a half-dozen incidents of elementary kids bringing weapons to school, weapons found in the backpack, weapons that come from the home,” Trump said. “That’s where the weapons, the guns, the ammunition that we find — particularly with elementary school kids — come from. They come from the home.”

We will continue to follow this investigation.