Investigators believe Shane Tamura, of Las Vegas, was trying to get up to the NFL offices after shooting several people in the lobby on Monday but entered the wrong elevator bank, Mayor Eric Adams said in interviews.

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.

The brain disease has most commonly been found in athletes in contact sports and others with a history of repeated brain trauma.