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

Investigators are trying to determine why a man targeted a Pennsylvania hospital, taking workers inside the intensive care unit hostage and holding one staff member at gunpoint as her hands were bound by zip ties.

A memorial is growing as a Pennsylvania community mourns the loss of a police officer on Saturday. The officer was killed in the line of duty when a gunman opened fire inside the UPMC York Memorial Hospital.