MILWAUKEE (CBS 58) -- There was a heavy police presence in downtown Milwaukee Thursday, May 15, after reports of shots fired on the fourth floor of the Zeidler municipal building.

Employees were advised to shelter in place as part of safety procedures. 

Milwaukee police say after a comprehensive search of the building, they did not locate any evidence that a shooting took place.

Earlier reports from a police source indicated that a former employee fired shots after being fired. 

Mayor Johnson spoke Thursday afternoon, also confirming that there is no indication shots were fired inside the building. 

An investigation is ongoing. 

This is a developing story. Stick with CBS 58 for updates on-air and online.