CINCINNATI (AP) — Police are trying to determine what led to gunfire at a hospital’s psychiatric services emergency room that left an unarmed security officer wounded and the gunman dead.

Cincinnati police indicated they would release updated information on their investigation sometime Thursday. The gunman hadn’t been identified as of Wednesday night.

Police believe he died of a self-inflicted gunshot after storming the University of Cincinnati Medical Center’s psychiatric services wing.

Police Chief Eliot Isaac said police couldn’t say immediately whether the man was known to employees or medical staff.

Police responded to an "active shooter" report in the area of UC Medical Center just before 2 p.m. Wednesday. Isaac said afterward that police were still piecing together the sequence of events, but didn’t believe any officers fired their weapons.