The gunman who killed four people in a Midtown Manhattan office building in July had chronic traumatic encephalopathy, the degenerative brain disease linked to repeated head injuries sustained in football and other contact sports, according to the New York City medical examiner’s office.
The disease, known as C.T.E., can be diagnosed only posthumously. Shane Tamura, the gunman, killed himself after the shooting spree at 345 Park Avenue.
The medical examiner “found unambiguous diagnostic evidence of Chronic Traumatic Encephalopathy, also known as C.T.E., in the brain tissue of the decedent,” according to a statement. “The findings correspond with the classification of low-stage C.T.E., according to current consensus criteria.”
Mr. Tamura, a former high school football player, shot himself in the chest after killing four people and left a note that said his motive was anger at the National Football League, which he blamed for hiding the effects of C.T.E. In the note, he asked that his brain be studied.
The police said Mr. Tamura, 27, drove from his apartment in Las Vegas and arrived in Manhattan and targeted the building because it housed the N.F.L. headquarters.
He killed Didarul Islam, a Police Department officer; Aland Etienne, a security guard behind a desk; Wesley LePatner, a senior executive at Blackstone who took cover behind a pillar; and Julia Hyman, who worked at Rudin Management. He also shot and wounded Craig Clementi, an employee for the N.F.L.