The shooter went on a gun rampage in the medical facility killing one colleague and injuring six others before turning the gun on himself.
Armed cops rushed to the Bronx Lebanon Hospital on Grand Concourse to reports of a man 'dressed in a white lab coat and carrying an M-16 assault rifle' at about 2.50pm local time.
Shots were reported fired on the 16th and 17th floor of the medical facility and the gunman shot himself dead around an hour after the incident began - after a failed attempt to set fire to himself, police said.
The shooter - named by police as former employee Dr. Henry Bello, 45 - is said to have hidden the assault rifle under his white lab coat as he walked into the hospital before opening fire.
Images have also emerged of the rifle he used in his terrifying shooting spree.