OMAHA, Neb. (AP) — The Douglas County Sheriff’s Office says an entrance screening officer violated some procedures when his gun accidentally fired inside the county courthouse.

The officer was checking the slide on the gun when it fired. The gun went off at a closed exit, and no one was hurt. The bullet pierced an X-ray machine and hit a concrete wall near the machine.

Douglas County Attorney Don Kleine said Friday that had it not been for the concrete wall, the bullet likely would have gone through a conference room and into his office. Kleine was not in the office at the time the gun went off.

The department says an internal investigation showed some procedures were violated and that corrective action will be taken.