The gunman who took his own life after killing four people and injuring an NFL employee this summer has been diagnosed with CTE.

Shane Tamura, 27, executed a lethal attack at a Manhattan office building that houses the NFL’s headquarters and several major financial firms.

After a note discovered in his wallet accused the NFL of concealing the brain injuries linked with football, Tamura himself was posthumously diagnosed with the degenerative brain disease often found in former football players.

On Friday, the New York medical examiner declared that Tamura had ‘unambiguous diagnostic evidence’ of low-stage chronic traumatic encephalopathy, commonly referred to as CTE, which can only be identified after death.

A three-page note retrieved from his wallet revealed that Tamura, a former high school football star, claimed he had CTE and urged those who discovered him: ‘Study my brain.’

‘There is no justification for the horrific and senseless acts that took place,’ an NFL spokesman said in response to the findings. 

Shane Tamura has been posthumously diagnosed with CTE following his gun attack in July

Tamura accused the NFL of hiding the effects of brain injuries linked with sport. Above is NFL commissioner Roger Goodell

‘As noted by the medical examiner, the science associated with this condition is still evolving, and the psychological and physical manifestations of CTE remain subjects of study.’

This disease impacts brain regions responsible for regulating emotions and behavior and is associated with concussions and head trauma typical in contact sports, with signs of the ailment discovered in both professional and high school athletes.

After more than a decade of denial, the NFL conceded the link between football and CTE in 2016 testimony before Congress, and has so far paid more than $1.4billion to retired players to settle concussion-related claims.

Tamura, a Las Vegas casino worker, shot himself in the chest after spraying bullets into the Manhattan office building at 345 Park Avenue on July 28, killing four people:  NYPD officer Didarul Islam, Blackstone executive Wesley LePatner, security guard Aland Etienne and real estate professional Julia Hyman.

Craig Clementi, who works in the NFL’s finance department, was reportedly shot in the back but survived.

Tamura had traveled across the country intending to target the NFL office, officials said, but took the wrong elevator.

Police have said Tamura had a history of mental illness. In September 2023, he was arrested on a misdemeanor trespassing charge after allegedly being told to leave a suburban Las Vegas casino and becoming agitated at being asked for his ID. Prosecutors later dismissed the case.

Tamura gunned down four people during a deadly attack in New York over the summer

FDNY and NYPD officers are seen responding to the shooting on July 28 in Manhattan

In the wake of the attack, the league recommended upgraded security measures for its franchises.

According to a memo obtained by The Athletic, the NFL recommended that league and team facilities have armed officers present whenever players or staff are there.

The memo also recommended weapons screening for anyone entering a league or team facility, and ‘updated risk assessments’ at every team and league facility.

Following the attack, NFL commissioner Roger Goodell was asked about the NFL being targeted, and told NBC: ‘It’s a difficult thing, particularly when you’re dealing with a senseless act like this.

‘There are no excuses for those senseless acts – they are hard for all of us to understand when it inflicts pain on people you know and care about and people we deal with on a daily basis.

‘That’s particularly hard but – as you know – these acts of senseless violence and hatred are happening around our country and our world far too often… we all have to continue to be vigilant and do what we can to protect ourselves and the NFL is going to do that with our employees and our people.’