A medical examiner has found that former high school football player Shane Tamura — who shot and killed four people before taking his own life in the Manhattan building that houses the NFL headquarters in July — had chronic traumatic encephalopathy (CTE).
CTE is a degenerative brain disease that has repeatedly been found in the brains of American football players, alongside athletes from other contact sports and soldiers.
The grim findings about Tamura’s brain highlight how prevalent the disease has become among football players. A 2023 study by researchers at the Boston University CTE Center found that 345 of 376 deceased former National Football League players had CTE.
Symptoms include depression, cognitive impairment, and suicidal thoughts.
According to a statement quoted by the New York Times, the examiner “found unambiguous diagnostic evidence” of CTE in Tamura’s brain tissue.
“The findings correspond with the classification of low-stage CTE, according to current consensus criteria,” the statement reads.
After taking his own life, the 27-year-old Tamura left behind a note that expressed anger at the National Football League. The former player accused the NFL of hiding the effects of CTE in favor of profits. He also asked for his brain to be studied and therefore chose to shoot himself in the chest, not the head.
Confusingly, Tamura appears to have targeted the wrong office in the building, though he did injure one NFL employee.
In a statement to the NYT, the NFL carefully sidestepped any culpability.
“There is no justification for the horrific and senseless acts that took place,” the sports league wrote. “As the medical examiner notes, ‘the science around this condition continues to evolve, and the physical and mental manifestations of CTE remain under study.’”
In a study published last year, researchers found that one-third of former professional football players reported that they believe they have CTE. However, since diagnosis requires an autopsy, it’s difficult to determine whether their symptoms were the result of CTE or other causes.
CTE arises from blows to the head and affects the region of the brain responsible for cognition and executive function. It can also affect the amygdala, which is associated with emotional control.
“There is damage to the frontal lobes, which can damage decision making and judgment,” Boston University CTE Center director Ann McKee told the NYT in July following the shooting. “It can also cause impulsivity and rage behaviors, so it’s possible that there’s some connection between brain injury and these behaviors.”
Tamura isn’t the first football player to perpetrate a mass shooting. In 2021, former NFL player Rock Hill killed six people before turning his gun on himself.
Examiners later found that he had an “unusually severe” form of CTE.
More on CTE: One Out of Three Former NFL Players Think They Have CTE, the Traumatic Brain Disease Linked to Murders and Suicides