Tamura killed four and badly wounded another before shooting himself in the chest.In the note, Tamura claimed to have CTE—chronic traumatic encephalopathy, a brain injury condition due to repetitive trauma to the brain—and that he wanted researchers to study his brain.

The man who killed four people in the New York City skyscraper that is home to NFL headquarters carried a note blaming the league for his mental health problems.

Meiko Locksley, one of 152 athletes diagnosed with CTE before even reaching the age of 30 as part of the Boston University CTE Center’s 2023 study, never made it past college football and began exhibiting signs of the disease in his 20s.