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:

The shooter, identified as Shane Devon Tamura, of Las Vegas, by the New York Police Department, also died via a self-inflicted gunshot wound after opening fire with an M4 rifle. Tamura shot multiple people in the lobby before taking the elevator to the 33rd floor, where he shot himself in the chest, N.Y.C. Police Commissioner Jessica S. Tisch said.