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 Monday, killing four people, including a New York City police officer, and wounding a fifth before taking his own life, officials said. The shooting took place at a skyscraper that is home to the headquarters of both the NFL and Blackstone,

A New York police officer, a “beloved” security guard, a young Cornell graduate and a senior executive with investment firm Blackstone were killed Monday when a lone gunman stormed a sprawling office tower in Midtown Manhattan and opened fire.