The man accused of carrying out a deadly shooting at a Park Avenue skyscraper in Manhattan believed he was suffering from chronic traumatic encephalopathy (CTE) — a degenerative brain condition linked to repeated head trauma, commonly associated with football players.

New York City Mayor Eric Adams stated that 27-year-old Shane Tamura may have been targeting NFL offices located in the building, where he allegedly shot and killed four people, critically injured another, and then took his own life on Monday night.

According to authorities, Tamura drove across the country armed with a semiautomatic rifle before launching the attack inside the building that houses NFL headquarters.

Tamura, who played high school football in California, was described in a 2014 article by The Santa Clarita Valley Signal as a standout running back who quickly gained recognition for his explosive performance on the field.

Investigators discovered a three-page handwritten note in Tamura’s wallet. In it, he requested that his brain be examined for CTE and accused the NFL of hiding the risks that football poses to the brain.
Notably, Tamura was never an NFL player, but his note suggests he believed the league bore responsibility for his condition.

Manhattan Shooter Left Note Claiming Brain Injury, Referenced NFL and CTE

Shane Tamura, the 27-year-old man who carried out a deadly shooting in a Manhattan skyscraper housing the NFL’s headquarters, had a note in his pocket claiming he suffered a traumatic brain injury. The note also made vague references to the NFL, which is located in the same building where the attack occurred.

What Is CTE?

Chronic traumatic encephalopathy (CTE) is a progressive brain disease believed to be caused by repeated head trauma. It leads to the degeneration of brain cells and can only be definitively diagnosed after death, through a brain autopsy.

Although rare and still not fully understood, CTE is not believed to result from a single concussion, but rather from repetitive impacts to the head. It is most often seen in athletes (especially football, hockey, and boxing) and military veterans. It has also been linked to second impact syndrome, when a second brain injury occurs before the first has healed.

A Harvard study of nearly 2,000 former football players found that about one-third believed they had CTE. Over 230 reported suicidal thoughts, and 176 said they’d been diagnosed with Alzheimer’s or dementia.

A Boston University report from 2023 revealed that 345 deceased former NFL players were posthumously diagnosed with CTE.

Researchers note the possibility of selection bias in these studies, as players or families affected by health issues may be more likely to participate.

Symptoms of CTE

There are no symptoms unique to CTE, but people diagnosed posthumously have often shown:

• Cognitive decline: memory loss, difficulty planning or concentrating

• Behavioral changes: impulsivity, aggression

• Mood issues: depression, apathy, emotional instability, substance abuse, suicidal thoughts

• Motor symptoms: tremors, balance issues, Parkinsonism, or ALS-like symptoms