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

A New York City police officer killed during a shooting at a Manhattan office tower is being laid to rest. NEW YORK (AP) — A New York City police officer who was among the four people shot and killed by a gunman during a rampage at a Manhattan office tower will be laid to rest Thursday.

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.

In the aftermath of New York’s deadliest mass shooting since 2000, authorities are investigating the motives and background of the man who opened fire in a midtown Manhattan office skyscraper, killing four people and then himself.