ST. PAUL (AP) -- Police in St. Paul are investigating how a loaded handgun ended up in the backpack of an elementary school student.

Sgt. Mike Ernster says the 8-year-old girl put her backpack on the floor at John A. Johnson Achievement Plus Elementary School Monday and heard a thud. Ernster says she opened the backpack and found the gun, then told her teacher about it. The girl wasn't sure how the gun ended up in her bag.

Police secured the gun, which belonged to the girl's mother.