An examination of former New England Patriots running back Mosi Tatupu’s brain showed signs of Chronic Traumatic Encephalopathy that is linked to head injuries, his ex-wife said.

Tatupu died of a heart attack in 2010 at age 54, but last year his former wife, Linnea Garcia-Tatupu, learned that some brain tissue was preserved from the autopsy and she offered it to the Boston University CTE Center, which conducts research on the brains of former athletes.

Tatupu’s brain tissue showed a buildup of tau, a protein, that was consistent with CTE.

His son, Lofa Tatupu, also played in the NFL for the Seattle Seahawks from 2005 to 2010.

“If I knew then what I know now, would I have encouraged Mosi’s dream? Would I have encouraged Lofa’s dream?” Garcia-Tatupu told The Boston Globe. “I wouldn’t have. The risk is not worth the reward.”

Tatupu was well liked by players and fans during his 13-year career with the Patriots, but Garcia-Tatupu said her husband’s behavior changed during the end of his playing days and led to drinking, forgetfulness and ultimately a divorce after a 20-year marriage.

Tatupu’s symptoms occurred in his 30s, much earlier than many NFL players have exhibited signs of CTE. Some players linked to CTE, including former San Diego Chargers linebacker Junior Seau and former Chicago Bears safety Dave Duerson — committed suicide.