A man who took hostages at UPMC hospital during a shooting that killed a police officer and wounded five others highlights the rising violence against U.S. healthcare workers.

YORK, Pa. - . The BriefA possible motive for the deadly hospital shooting in York, Pennsylvania, is still unknown.Officials say the suspect had recent contact with the ICU "for a medical purpose."The hospital remained closed to visitors on Sunday.

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