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,

An officer was killed, and six others were injured after a man armed with a pistol and zip ties entered into a Pennsylvania hospital's intensive care unit Saturday afternoon. Police were called to UPMC Memorial Hospital on Innovation Drive and Roosevelt Avenue in York County,

A gunman, armed with a handgun and carrying zip ties, went inside UPMC's ICU, and took staffers hostage before he was ultimately killed by police in a shootout, the York County DA said.