Marshawn Kneeland’s Cause of Death Revealed at Age 24

The Marshawn Kneeland cause of death was officially confirmed on Tuesday, July 7, 2026. Researchers at the Boston University CTE Center announced that the Dallas Cowboys defensive end died by suicide. The post-mortem examination also found stage 1 chronic traumatic encephalopathy (CTE).

Dr. Ann McKee, director of the Boston University CTE Center and chief of neuropathology for the VA Boston Healthcare System, said she was not surprised to find CTE in Kneeland’s brain. However, researchers stressed that the diagnosis should not be viewed as the cause of his death. Instead, the case adds to ongoing research into repeated head trauma and its long-term effects on athletes.

Kneeland died on Nov. 5, 2025, at age 24. Authorities previously said he died from an apparent self-inflicted gunshot wound after leading Texas Department of Public Safety troopers on a pursuit north of Dallas. Investigators later found him near his crashed vehicle along the Dallas Parkway in Frisco.

What the CTE diagnosis means  and what it doesn’t

Dr. McKee said Kneeland played during an era with improved concussion protocols and safer helmet technology. Even so, he still developed stage 1 CTE. Researchers say the finding highlights that the disease can develop despite advances in player safety.

The Concussion Legacy Foundation emphasized that the diagnosis should not be interpreted as the reason for Kneeland’s death. Suicide is a complex issue with many contributing factors. Current medical evidence does not support using a post-mortem CTE diagnosis alone to explain why someone died by suicide.

Dr. Chris Nowinski, the foundation’s CEO, said Kneeland’s case demonstrates that even younger players with relatively short professional careers may develop CTE.

Kneeland’s family shares the diagnosis

Kneeland’s family, including his girlfriend Catalina Mancera, released a statement through the Concussion Legacy Foundation. They said learning about the diagnosis helped provide context for some of the challenges he may have experienced.

The family also said they chose to share the findings to raise awareness about the neurological risks facing athletes in contact sports. They asked the public to remember Kneeland for the person he was instead of focusing solely on the circumstances of his death.

His final NFL game

Just two days before his death, Kneeland delivered one of the biggest plays of his career. He recovered a blocked punt for a touchdown during the Cowboys’ game against the Arizona Cardinals on Nov. 3.

Former defensive coordinator Mike Zimmer later described Kneeland as tough, hardworking and eager to improve. That memorable touchdown has since taken on added significance for teammates and fans reflecting on his life.

His family and lasting legacy

Kneeland’s path to the NFL included personal heartbreak. His mother, Wendy Kneeland, died unexpectedly in February 2024, only months before the Cowboys selected him in the second round of the NFL Draft. He often spoke about her support and wore a necklace containing her ashes during games.

More than six months after his death, Mancera gave birth to their son, Makhai, on June 11, 2026. The family’s statement said they hope sharing Kneeland’s diagnosis will encourage greater awareness of brain health, player safety and mental health.

Kneeland appeared in 18 games over two seasons with Dallas, recording 26 tackles and one sack. The Cowboys described him as a beloved teammate when announcing his death in November 2025. As of Tuesday’s CTE announcement, the organization had not issued an additional statement.

End with the suicide prevention resource

If you or someone you know is struggling or in crisis, call or text 988 or visit 988lifeline.org to reach the Suicide & Crisis Lifeline. Help is available 24 hours a day, seven days a week.

This revision reduces long sentences, varies sentence openings, improves readability, and preserves the medically important distinction that CTE was found during the brain examination but has not been established as the cause of Kneeland’s suicide.