A man stalked through a Manhattan office tower firing a rifle, killing four people, including a New York City police officer, and wounding a fifth before taking his own life, officials said.

The first word of a deadly shooting spree during rush hour in Midtown Manhattan on Monday came into the New York 911 system at 6:28 p.m. (2228 GMT) and more calls soon flooded in, according to a detailed recount of the shooting that left at least five dead,