Four people were killed and a fifth was injured in a mass shooting at a Midtown Manhattan office building on Monday.

A married father of two with a third child on the way, the 36-year-old was working a New York Police Department-approved private security detail, in uniform, when he and three other people were killed Monday at the Manhattan skyscraper that houses the NFL's headquarters and other corporate offices.

Thousands of familly, friends and colleagues are expected to gather to mourn the NYPD officer killed in this week’s Manhattan office attack at a funeral on Thursday, a day after another grieving family laid their loved one to rest,