Chronic traumatic encephalopathy, or CTE, is a brain disease linked to repeated hits to the head, often seen in military veterans and athletes.

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.

Shane Devon Tamura — the man who killed at least four people in a New York City office building — claimed in a suicide noted that he suffered from chronic traumatic encephalopathy (CTE) while slamming the NFL. “Study my brain please,” Tamura, a former high-school football player, wrote in the note. "I'm sorry."