A New York City police officer and three other people were shot and killed inside a Midtown Manhattan office building on Monday evening by a gunman armed with a high-powered rifle, police confirmed.The suspect,

The attacker was armed with an M4 rifle when he opened fire inside a skyscraper at 345 Park Avenue, Manhattan.

Four people, including an off-duty New York City police officer, were killed Monday when a gunman carrying a rifle opened fire inside a Midtown Manhattan office tower, authorities said.