Minneapolis police spent more than two hours Friday searching a downtown office building after a report of possible shots fired, but said they found no evidence of a shooting.
Workers in the building were told to shelter in place during the search. The 11-story building includes some offices of Target Corp.
Acting Chief Janee Harteau said an initial caller heard a popping sound. It was said to be coming from the 10th floor.
Police say a preliminary investigation showed that maintenance workers were using a construction tool on the upper floors that mimicked the sound of gunfire.
The building search came less than two months after a gunman fatally shot six people at a Minneapolis business after he was fired.