The New York City medical examiner’s office has confirmed a disturbing detail about the gunman responsible for the deadly July shooting at a Midtown Manhattan office building: he suffered from chronic traumatic encephalopathy (C.T.E.), a degenerative brain disease. This condition is notoriously linked to repeated head injuries often sustained in football and other high-impact sports.
C.T.E. can only be definitively diagnosed after death. Shane Tamura, the perpetrator of the violent spree at 345 Park Avenue, took his own life following the incident.
An official statement from the medical examiner’s office revealed “unambiguous diagnostic evidence of Chronic Traumatic Encephalopathy, also known as C.T.E., in the brain tissue of the decedent.” The findings indicated a “low-stage C.T.E.” classification, consistent with current medical standards.
Tamura, who played high school football, died from a self-inflicted chest wound after shooting four people. A note discovered afterwards indicated his motive: profound anger at the National Football League, which he accused of hiding the severe effects of C.T.E.
Police reports detail how 27-year-old Mr. Tamura traveled from his Las Vegas apartment to Manhattan, specifically targeting the building at 345 Park Avenue, which houses the NFL headquarters. This address tragically became the site of a rampage that claimed five lives, including his own.
The assailant’s note, from which police provided excerpts, vehemently condemned the National Football League. He stated the league had prioritized profits over acknowledging the severe dangers of brain trauma associated with the sport.
Mr. Tamura’s family has not yet commented on these findings.
This diagnosis reignites critical discussions about the potential long-term risks of participating in tackle football, even at the youth level.
Mr. Tamura, whose football career ended after high school, specifically referenced C.T.E. in his note. He asserted that the NFL had concealed the dangers of brain trauma for financial gain, leading police to believe his actions were an act of vengeance against the league.
Over the past two decades, numerous former athletes from contact sports like football, boxing, and hockey have been diagnosed with C.T.E. This has significantly increased public awareness of the sport’s dangers, and researchers have advanced their understanding of the disease and its symptoms. Despite this, leaders in the NFL and other leagues have generally been reluctant to fully acknowledge the direct link between their sports and brain trauma.
C.T.E. frequently impacts the superior frontal cortex, a crucial area for cognitive functions such as working memory, planning, and abstract reasoning. It also often affects the amygdala, which plays a vital role in emotional control, aggression, and anxiety. Common symptoms include difficulty managing aggression and impulses, varying degrees of dementia, mood swings, impaired judgment, and disorganized behavior.
Most reported cases of C.T.E. involve former athletes who played contact and collision sports for 15 to 20 years, likely enduring thousands of head impacts. However, researchers caution about selection bias in studies, as many families donate brains due to observed symptoms.
With increasing knowledge of the disease, the brains of younger athletes are now being donated for study, with some also showing evidence of C.T.E., though typically less severe. At 27, Mr. Tamura joins this growing group of younger individuals diagnosed with the condition.
Regardless of the individual’s age, researchers remain cautious about directly linking C.T.E. to specific behaviors like murder or suicide, recognizing that numerous other factors could influence such decisions.
Dr. Ann McKee, director of the Boston University C.T.E. Center, who has examined thousands of brains from athletes and others with brain trauma, emphasizes the limited understanding of the connection between violent, impulsive behavior and C.T.E., stressing the need for further research.
“There is damage to the frontal lobes, which can damage decision-making and judgment,” Dr. McKee recently stated. “It can also cause impulsivity and rage behaviors, so it’s possible that there’s some connection between brain injury and these behaviors.”
Several high-profile cases involving former football players committing violent crimes have drawn national attention. A notable example is Aaron Hernandez, the former New England Patriots tight end, who was convicted of murder and later died by suicide in jail. Hernandez, also 27 at his death, was found to have a severe form of C.T.E., comparable to damage seen in players decades older.
Phillip Adams, who tragically shot and killed six people before taking his own life in Rock Hill, S.C., in 2021, also had an “unusually severe” form of C.T.E. He was 32 and had played six seasons in the NFL.
Other former NFL players who died by suicide, such as Dave Duerson, deliberately shot themselves in the chest to ensure their brains could be studied, with Duerson explicitly requesting a brain examination in his suicide note.
However, researchers point out that these individual cases may not represent the broader population of individuals living with C.T.E.
“I would never draw a direct line between someone’s brain pathology and any specific violent act, because the majority of people who have C.T.E. never committed anything like this,” Dr. Daniel H. Daneshvar, chief of brain injury rehabilitation at Harvard Medical School, recently explained.
The risk of developing C.T.E. was traditionally thought to be limited to those who endured years of professional contact sports. However, more recent diagnoses in younger athletes from various contact sports, including some who never played professionally or even collegiately, have expanded this understanding.
A Boston University study published in 2023 examined the brains of 152 contact-sport athletes who died before age 30 and whose families had concerns about brain disease. Over 40% of these athletes showed evidence of C.T.E., with most having played at no higher than the high school or college levels. Of the 63 individuals diagnosed with C.T.E., 48 had played football.
These younger athletes, like their older counterparts, displayed a tau protein, a hallmark of C.T.E., in specific brain regions. However, the tau concentration was lower, and their cognitive symptoms were similar to those of other young athletes without C.T.E. Researchers suggest this could indicate that the smaller tau accumulation might not be the sole cause of their symptoms, implying other factors may be at play.
“The message here is that there’s less scientific understanding of what’s driving the symptoms in these younger players, and whether it’s related to brain trauma or perhaps other things,” commented Gil Rabinovici, a professor of neurology and radiology at the University of California, San Francisco. He added, “It’s going to be important to look at other brain changes that are not tau-related. We should be very cautious in trying to attribute their behavior to what we find in the brain.”
Without a definitive test for C.T.E. in living individuals, athletes like Mr. Tamura may attribute their cognitive issues to the disease. Dr. Rabinovici cited a survey of 4,180 former professional football players, where 34.4% believed they had C.T.E. based on symptoms like headaches, cognitive difficulties, depression, and suicidal thoughts.
Mr. Tamura’s mother and New York police officials confirmed he was prescribed medication for anxiety, depression, and bipolar disorder. His suicide notes revealed an obsession with brain injuries, firmly linking his poor mental health to his football-playing past and repeated head impacts.
Dr. Rabinovici and other researchers continue their dedicated work to develop a diagnostic test for C.T.E. in living patients. Promising techniques involve blood tests and brain imaging to detect the tau protein in specific brain areas, a “slow and steady” progress, he noted.
After years of public relations challenges and increasing evidence linking football to C.T.E., the NFL’s top health and safety official publicly acknowledged this connection in 2016. The league has since taken steps to guide children away from traditional tackle football, advocating for safer tackling methods and promoting flag football as an alternative.