A police officer and two civilians were shot at a Midtown Manhattan office building that houses The Blackstone Group and NFL headquarters in what officials were calling an active shooter investigation.

A police officer and three other people were killed after a gunman opened fire Monday evening at a Midtown Manhattan office building that houses The Blackstone Group and NFL headquarters, police

"To the other victims -- people just trying to make a living, do their jobs -- our hearts are broken, and we, too, grieve with your families." Here's what we know about the victims: Didarul Islam, 36,