NEW YORK (TNND) — A New York City police officer who was among the four killed by a gunman at a Midtown Manhattan office building will be laid to rest on Thursday. Officer Didarul Islam, 36, was shot and killed on Monday in the building that is home to the National Football League's headquarters while working as an off-duty security guard.

The Nevada man behind a shooting spree in a Midtown Manhattan office building may have originally been targeting for the NFL headquarters, sources say. Police sources told ABC News Tuesday that a page of the note found in suspect Shane Tamura's pocket alleged the National Football League had concealed the dangers football contact could cause to players' brains to maximize earnings.

Early Tuesday, Officer Islam’s body was draped in the NYPD flag as it was moved from the hospital to an ambulance, with fellow officers standing at attention.