A 5-year-old student at Anne E. Moncure Elementary School in Stafford County, Virginia, “inadvertently” brought a gun to school Thursday morning, the sheriff’s office said.

According to authorities, the firearm was found inside the student’s backpack during class. It was confiscated by staff.

“The investigation revealed the student had inadvertently taken an adult’s backpack from the vehicle instead of his own during drop-off,” the Stafford County Sheriff’s Office said in a release.

Officials said everyone involved was cooperative.

Charges are pending for the gun owner.