A gunman who killed four people inside a Manhattan office tower blamed his mental health problems on the National Football League and intended to target its headquarters but took the

Study my brain please,” read a note left by the gunman accused of killing four people in a building that houses NFL’s headquarters

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,