New York City medical examiner announced on September 26 that Shane Tamura, the man who shot and killed four people in a Manhattan office building in July, was found to have chronic traumatic encephalopathy (CTE). This diagnosis aligns with his self-disclosure in a suicide note.
The medical examiner’s statement revealed that Tamura’s brain showed “clearly diagnosable signs of chronic traumatic encephalopathy (CTE),” classified as a “low stage lesion.” CTE is a degenerative brain disease caused by repeated head impacts, with symptoms that may include emotional instability, behavioral abnormalities, and cognitive decline. However, the full progression and effects of CTE are still under ongoing research and can only be diagnosed postmortem.
The incident occurred on July 28 this year when the 27-year-old Tamura entered the office building located at 345 Park Avenue in New York City with an M4 assault rifle and indiscriminately opened fire in the lobby. According to the police, Tamura had intended to target the National Football League (NFL) headquarters inside the building but mistakenly ended up on the 33rd floor due to elevator error, where he continued shooting before ultimately taking his own life.
Three suicide notes were found on Tamura, in which he claimed to have CTE and demanded studies on his brain while accusing the NFL of concealing the risks of brain injuries. In response, the NFL stated that there is no justification for this “horrendous and senseless act of violence” and emphasized that relevant scientific research is still ongoing.
In 2016, the NFL acknowledged the connection between American football and brain injuries and has paid over $1.4 billion to retired players for concussion and related disease claims.