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,

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.

Cops encountered Archangel-Ortiz holding a female staffer at gunpoint with her hands bound, officials said. The officers engaged Archangel-Ortiz in a firefight, killing him. Archangel-Ortiz wounded two cops and killed a third, who was identified as Andrew Duarte, 30, of the West York Borough Police Department.

A 49-year-old gunman was shot and killed by police after they said he held multiple UPMC staff members hostage and shot multiple people.

One officer was killed and at least five others were were shot in a hostage situation at a hospital in York County, Pennsylvania, according to state officials.

A gunman and a responding officer were killed after shots were fired Saturday at a hospital in central Pennsylvania.

Anguish and anger at the very recent loss of a loved one apparently spurred on the man who would target the intensive care unit at a Pennsylvania hospital Saturday morning, a senior law enforcement official briefed on the investigation told ABC News.