Killer at NFL Building Had CTE: Medical Examiner

The man who police say shot to death four people in a Manhattan office building housing NFL headquarters last July had the degenerative brain disease CTE, the New York City medical examiner said Friday. The 27-year-old, who had played high school football, killed himself after leaving a note linking his mental health struggles to head injuries sustained on the field with the plea "study my brain." The medical examiner described the diagnosis of low-stage chronic traumatic encephalopathy as "unambiguous," NBC News reports.

Most often with professional football players, CTE results from repeated head trauma. Experts said the case of Shane Devon Tamura is part of a broader, often overlooked pattern: High school athletes can and do develop CTE, even without progressing to college or professional sports. "We know high school football players can get CTE," said Chris Nowinski, who leads the nonprofit Concussion Legacy Foundation. Nowinski called for stricter safety measures in school sports, arguing that no more research is needed to justify changes.

The NFL released a statement saying, "As the medical examiner notes 'the science around this condition continues to evolve, and the physical and mental manifestations of CTE remain under study,'" per ABC News. Tamura's history of depression and previous threats of self-harm had been documented, but the full relationship between his mental state and CTE remains unclear. Medical experts caution that while the disease is linked to symptoms like aggression and depression, much is not yet known, and that many factors influence behavior. CTE can only be diagnosed posthumously, complicating research and prevention efforts.