New York City is mourning an NYPD officer and three other people killed in Monday night's shooting inside an office building in Midtown Manhattan. Officer Didarul Islam was in uniform working as a security guard for a private company at the time of the shooting,

Didarul Islam, the NYPD officer killed by a rampaging gunman in a mass shooting in a Park Avenue skyscraper, was a Bangladeshi immigrant who joined the force to leave behind a legacy his family could be proud of,

New York's mayor says the father of two was doing what he did best and protecting New Yorkers when he was shot dead on Monday evening.