Marshawn Kneeland’s family released Tuesday the results of his post-mortem brain tissue analysis after the Cowboys defensive lineman died by suicide in November 2025.
Per the release from the Concussion & CTE Foundation, Boston Univeristy CTE Center researchers diagnosed the 24-year-old with stage 1 chronic traumatic encephalophathy (CTE).
It’s the lowest level on a scale of 1 to 4.
Kneeland, who was selected 56th overall by Dallas in the 2024 NFL Draft, died by suicide after a police pursuit on Dallas Parkway.
He was found dead from an apparent self-inflicted gunshot wound, per Frisco police, who explained they received information during their pursuit that Kneeland had previously expressed suicidal thoughts.
“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, per Pro Football Talk.
“Thanks to the generosity of our brain donor families, we now better understand the earliest stages of CTE, and it is bringing us closer than ever to diagnosing it during life. My team and I are fully dedicated to finding effective treatments and a cure for CTE.”
Per the 911 dispatch audio obtained by TMZ, an operator said Kneeland’s girlfriend, Catalina Mancera, received a concerning message from him and she was trying to contact his agent.
Mancera quoted Kneeland saying he would “end it all.”
Mancera recently gave birth to her and Kneeland’s child on June 11. She posted several photos of the infant wearing a onesie with a design of Kneeland in his Cowboys jersey.
“My favorite gift from you 🤍,” she wrote in the caption.
Kneeland’s death came just two days after he played 17 snaps during the Cowboys’ 27-17 loss to the Cardinals.
If you are struggling with suicidal thoughts or are experiencing a mental health crisis, you can call or text 988 or chat at 988lifeline.org for free and confidential crisis counseling.
[Notigroup Newsroom in collaboration with other media outlets, with information from the following sources]
