Former Dallas Cowboys defensive end Marshawn Kneeland had a brain abnormality linked to repeated head trauma when he killed himself after a high-speed chase with police in November 2025. The findings of a postmortem analysis of Kneeland's brain tissue were released Tuesday by his family through the Concussion and CTE Foundation. Researchers at the Boston University CTE Center determined Kneeland was in stage one of four of chronic traumatic encephalopathy. Kneeland was 24. He had played at Western Michigan University, before he was selected by the Cowboys in the second round of the 2024 NFL draft.