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, 36, was a father of two, with a third on the way, and was working a second job as a security guard at the building where shots rang out.

Didarul Islam, a 36-year-old New York Police Department officer, was among four people killed Monday evening in Midtown Manhattan when a gunman stormed the lobby of the sprawling 345 Park Avenue office tower and opened fire.