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 mass shooting at UPMC Memorial Center has left the gunman and a police officer killed and multiple hospital staff injured.

Authorities described the shooting of a gunman who opened fire at a Pennsylvania hospital as “absolutely justified, beyond any and all doubt.”

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.

The attacker who killed a police officer and took three people hostage at a Pennsylvania hospital was identified Sunday, as authorities said he visited the hospital before. Diogenes Archangel-Ortiz, 49,

The suspect, Diogenes Archangel Ortiz, entered the hospital with handgun and zip ties Saturday morning and took several staff members hostage, state officials said.

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,