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 executive was shot and killed in the lobby of the ritzy Park Avenue office tower when gunman Shane Tamura opened fire.

A police officer and at least four other people were shot and killed — and several others injured — by a crazed gunman who stormed a swanky Midtown skyscraper early Monday evening — before turning