Four people were killed and a fifth was injured in a mass shooting at a Midtown Manhattan office building on Monday. The injured victim was an employee at the NFL, according to NFL Commissioner Roger Goodell. Here's what we know about the four people killed:

A man stalked through a Manhattan office tower firing a rifle, killing four people, including a New York City police officer, and wounding a fifth before taking his own life, officials said.

The victims of the Manhattan office building shooting are identified as NYPD Officer Didarul Islam, Blackstone executive Wesley LePatner, Cornell grad Julia Hyman and security officer Aland Etienne.