Off-duty NYPD officer Didarul Islam is being remembered as a hero after he was killed while providing security for an office building in Manhattan when a gunman opened fire.

Four people have been killed, including one NYPD officer, after gunfire erupted in Midtown Manhattan Monday afternoon, officials said. Here's a look at what happened in New York Monday evening. All time stamps are based on East Coast times. Four people were shot and killed in Midtown Manhattan on Monday.