A gunman who held medical staff hostage before killing a police officer and wounding five others at a hospital in south-central Pennsylvania Saturday is believed to have visited the facility in the days leading up to the incident,

Investigators are trying to determine why a man targeted a Pennsylvania hospital, taking workers inside the intensive care unit hostage and holding one staff member at gunpoint as her hands were bound by zip ties.

Violence against healthcare workers is on the rise as seen by an attack at a Pennsylvania hospital. A gunman took hostages before exchanges of gunfire that killed a police officer and wounded five other people at a York County,