Kneeland died by suicide in 2025 after police chase
Researchers determine he was in stage one of four
Brain disease can be diagnosed only after death
Former Dallas Cowboys defensive end Marshawn Kneeland, who died by suicide in November 2025 after a high-speed chase with police, had early stage chronic traumatic encephalopathy, a brain abnormality linked to repeated concussions, his family announced Tuesday.
The Boston University CTE Center, which investigates the long-term consequences of repetitive brain trauma in athletes and others, analyzed Kneeland’s brain tissue after his death. Researchers determined Kneeland, who was 24, was in stage one of four of CTE.
In the US, you can call or text the National Suicide Prevention Lifeline on 988, chat on 988lifeline.org, or text HOME to 741741 to connect with a crisis counselor. In the UK and Ireland, Samaritans can be contacted on freephone 116 123, or email jo@samaritans.org or jo@samaritans.ie. In Australia, the crisis support service Lifeline is 13 11 14. Other international helplines can be found at befrienders.org