Lester Mendoza, who specializes in pulmonary critical care, was present when the perpetrator was informed about his loved one's death.

Lester Mendoza took to Facebook to share his story of interacting with the shooter, Diogenes Archangel-Ortiz, days before he held staff hostage and shot six people, killing a police officer at the hospital.

UPMC announced this morning via a Facebook post that it has closed Memorial Hospital in West Manchester Township to visitors in the wake of a hostage incident Saturday that left one police officer dead, two injured and several staff members injured. The health care system did not say when visitors to patients would once again be welcome.