The gunman who held intensive care unit staff hostage at UPMC Memorial Hospital in Pennsylvania before killing a police officer and injuring five other people Saturday believed that more could have been done to save his wife,

Violence against healthcare workers is on the rise as seen by an attack at a Pennsylvania hospital. 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, 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.

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,