A gunman armed with an assault-style rifle killed four people inside a Manhattan skyscraper that houses the headquarters of the NFL and offices of several major financial firms and then shot himself dead,

Islam was married and had two young sons. He was a three and a half year veteran of the police department, Police Commissioner Jessica Tisch said in the press conference.

Police swarmed Midtown Manhattan on Monday during "an active shooter investigation" amid reports a police officer had been struck.