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:

An NYPD officer, a Blackstone executive, a Rudin Management associate and a security guard were killed in the shooting at Manhattan's 345 Park Avenue.

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