The man who authorities say entered a Pennsylvania hospital with zip ties and a pistol over the weekend had recent contact with the hospital's intensive care unit, where he took staff members hostage and was killed in a shootout that left a police officer dead and others injured.

A man who took hostages in a Pennsylvania hospital during a shooting that killed a police officer and wounded five other people highlights the rising violence against U.S. healthcare workers and the challenge of protecting them.

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,