Manhattan Shooter's Note Reportedly Referenced CTE

Police were still trying to piece together what prompted Monday's deadly shooting inside a Manhattan high-rise, but the gunman's suicide note may provide clues. Both CNN and ABC News report that the shooter claimed in the note to have suffered from the brain disease CTE. The skyscraper where the shooting took place houses offices for the NFL, suggesting he had a grievance with the league over its handling of the issue, per CNN. Details:

• The shooter has been identified as 27-year-old Shane Devon Tamura of Las Vegas, per the New York Times. Police say he fatally shot four people in the Park Avenue skyscraper and wounded five others, before taking his own life.
• Tamura played high school football in California, and a former teammate described him as a great player and the "biggest goofball in the world" as a teenager, per NBC News. Police say he had a "documented mental history," and his note reportedly asks that his brain be studied. CTE is linked to head trauma, making it a big concern of former football players. "You can't go against the NFL, they'll squash you," the gunman's note reads, according to CNN.

• An NFL employee was seriously injured in the shooting, said league president Roger Goodell.
• A New York City police officer, 36-year-old Didarul Islam, was among those killed, per USA Today. He was working as an off-duty security officer in the building at the time, and police say he was shot in the lobby of the building. The other people killed have not been identified. Islam is a native of Bangladesh, and he is survived by two sons and a pregnant wife.