A man exited a double parked BMW with an M4 rifle and then walked toward the skyscraper that is home to the headquarters of both the NFL and Blackstone, one of the world’s largest investment firms, as well as other tenants on Monday evening, according to surveillance video.

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 note found in the gunman's wallet was critical of the NFL and mentioned CTE. The 27-year-old wrote, “Study my brain please. I’m sorry."

Four people were killed, including an off-duty New York City police officer, when a gunman opened fire in an office tower before fatally shooting himself, officials said.

The first word of a deadly shooting spree during rush hour in Midtown Manhattan on Monday came into the New York 911 system at 6:28 p.m. (2228 GMT) and more calls soon flooded in, according to a detailed recount of the shooting that left at least five dead,