A Manhattan gunman, Shane Tamura, who suspected he had chronic traumatic encephalopathy (CTE), killed four people and himself in a Park Avenue skyscraper. Tamura, a former high school football player, reportedly targeted NFL offices, leaving a note blaming the NFL for concealing football's brain risks. CTE is a degenerative brain disease linked to repeated head trauma, often diagnosed posthumously. The incident highlights ongoing concerns about the NFL's handling of concussions and the link between CTE and violent behavior.

Prepared by Olivia Bennett and reviewed by editorial team.