The gunman who killed four people, including an NYPD officer, reportedly had a grievance against the NFL and blamed football for issues with CTE.

Shane Tamura, the shooter behind the deadly rampage in Midtown Manhattan,​ was apparently targeting NFL offices, NYC Mayor Eric Adams says.

Shane Tamura, the Park Ave. gunman who killed an NYPD officer and three others before taking his own life, left behind a suicide note saying he suffered from CTE, a brain injury often linked to playing football, and was targeting the NFL — but took the wrong elevator, officials said Tuesday.