Late Dallas Cowboys Defensive End Diagnosed with CTE

ARLINGTON, TX — The former Dallas Cowboy who died by suicide following a police chase was diagnosed with CTE.

Marshawn Kneeland, a 2024 second-round pick, died by suicide on Nov. 6, 2025, following a vehicle pursuit with police. After crashing his vehicle, he then fled on foot before suffering a fatal self-inflicted gunshot wound. In the chase, Kneeland reached speeds well over 100 miles per hour. 

He was 24 years old.

Kneeland’s family donated his brain for research, and he was posthumously diagnosed with Stage 1 chronic traumatic encephalopathy.

According to an ESPN report, Kneeland had several mental health incidents before being drafted by the Dallas Cowboys. Those include his time at Western Michigan when he had to turn in a firearm until he was cleared by a counselor and one instance where he was laying on railroad tracks. 

Kneeland is just one of many NFL players who has dealt with CTE. Some of the higher-profile athletes to be diagnosed are Junior Seau, Aaron Hernandez, Demaryius Thomas and Mike Webster, who was one of the first players to ever be diagnosed.