Police say the gunman in the Manhattan office building shooting tried to target NFL offices. In a note found in the gunman's pocket and obtained by CBS News, he alluded to having CTE. A former high school football player,

The Manhattan high-rise shooter, a former high school football player, left a note referencing the brain disease CTE and appeared to have targeted the NFL’s offices, authorities said.

The man who opened fire in a Midtown Manhattan office building, killing four people and wounding a fifth, appeared to be targeting the NFL headquarters and had a note claiming he suffered from CTE, police sources told ABC News.