Police say a third-grader at a Minnesota school got his finger on the trigger of a liaison officer's holstered gun, causing it to fire a bullet into the floor.

Maplewood police say no one was injured when the gun fired Monday as the officer was talking with students in the gym at Harmony Learning Center.

The school is for students with special needs. The officer, who is assigned to the school to build relationships with students, was sitting on a bench when a boy next to him pressed the trigger. Police say the officer didn't know the boy was touching his gun until it fired.

Authorities say the holster has a trigger guard that typically prevents the trigger from being touched or pulled, but the boy was able to reach inside with his small finger and pull the trigger.

Maplewood police say they're taking another look at the design of the holster in order to prevent future situations. Maplewood communications manager Joe Sheeran says the officer has not been placed on administrative leave.