Marshawn Kneeland, the Dallas Cowboys player who died by suicide at 24 last year, was found to have stage 1 CTE, researchers have said.
Kneeland died in Plano, Texas, following a police pursuit that began when he allegedly failed to stop for a traffic violation in nearby Frisco on November 6.
His death came about two days after he scored his first NFL touchdown for the Cowboys, prompting an outpouring of tributes from teammates, fans and figures across the league.
In the first significant update on the circumstances surrounding his death in months, Kneeland’s family shared findings released through the Boston University CTE Center confirming that he had been diagnosed with chronic traumatic encephalopathy, known as CTE.
“Unfortunately, I was not surprised to find CTE in the brain of Mr. Kneeland, because we have found this progressive brain disease in nearly half of the athletes we’ve studied who have died before the age of 30,” said Dr. Ann McKee, director of the Boston University CTE Center.
Kneeland’s girlfriend, Catalina Mancera, who was pregnant at the time of his death and has since welcomed their son, also shared an emotional message following the diagnosis.
Kneeland died by suicide after a police chase in suburban Dallas in November
Kneeland, pictured with his girlfriend Catalina Mancera, was later diagnosed with CTE
‘While this diagnosis does not change the tragedy of his passing, it provides important context about some of the struggles he may have been facing,’ she said.
‘We share this information to help people understand what NFL and other high contact sport athletes might be struggling with. Raising awareness is important to us.
‘We continue to remember Marshawn with compassion for the person he was, rather than defining him by the final moments of his life.’
Last month, Mancera took to Instagram to reveal the birth of a baby boy, named Makhai, seven months on from the death of Kneeland.
Alongside the post, she wrote: ‘My favorite gift from you. June 11, 2026.’
Dr. Chris Nowinski, Concussion & CTE Foundation CEO, added: ‘Mr. Kneeland played in the modern era of concussion protocols and better helmets, and yet he still developed CTE
‘We have no reason to believe the current generation is at a lower risk of CTE than previous generations. Concussion protocols do not prevent CTE, because CTE is caused by repeated head impacts, not just concussions.
‘If we want to reduce CTE risk, we must implement CTE prevention protocols and aggressively reduce the number and strength of head impacts at every level of the game.’
In a statement, Kneeland’s girlfriend Mancera said: ‘We continue to remember Marshawn with compassion for the person he was, rather than defining him by the final moments of his life.’
Kneeland’s tragic death at the age of 24 on November 6th sent shockwaves across the NFL
Stage 1 is the earliest and lowest stage of the CTE scale, which ranges from 1-4.
According to the CTE Society, stage 1 can be marked by ‘short-term memory problems, depression, aggressive tendencies, explosivity, and executive function issues.’
The 24-year-old was found dead on Nov 6 from what police said was an apparently self-inflicted gunshot wound, hours after being pursued by officers who had attempted a traffic stop in suburban Dallas.
Kneeland died during the Cowboys’ bye week, days after scoring a touchdown in team’s 27-17 loss to Arizona Cardinals.
They played their first game without him last Monday night, winning 33-16 at the Las Vegas Raiders.
Kneeland drove at nearly 150mph before crashing into another car on the night of his death, according to a police report obtained by TMZ.
A Texas Department of Public Safety officer clocked him speeding at around 10:30pm on November 5. After following him, he then saw the late NFL player making ‘several unsafe lane changes’ as he passed other cars.
The officer claims he attempted to pull Kneeland over but he did not comply and, before long, the Dodge Charger disappeared out of view.
Kneeland’s vehicle was discovered abandoned on a grassy area by the side of the road
Kneeland’s girlfriend Mancera has given birth to their child, Makhai last month
According to reports, police found the car minutes later. It had crashed into another vehicle before stopping in a field but Kneeland was not there.
Inside the car, police claim to have found an empty gun holster but no firearm. The authorities then launched a search for Kneeland – including using dogs.
His body was eventually found in a port-a-potty around 1.30am on November 6. He had reportedly suffered a fatal – and self-inflicted – gunshot wound.
The Cowboys star had earlier sent his family a group text saying ‘goodbye’ during the drama involving the Texas Department of Public Safety troopers, according to a police audio dispatch.
Kneeland’s girlfriend Mancera also warned the police that the NFL player had a gun and that she feared he would kill himself.
