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."

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.

The consistent belief from the NYPD, the mayor’s office, and city officials is that NFL headquarters was indeed the target of the attack. Reportedly the note in Tamura’s possession asked that his brain be studied following his death, which would be possible considering he died of a self-inflicted gunshot wound to the chest.