Former Chicago Bears safety Dave Duerson died of a self-inflicted gunshot wound to the chest, a source with knowledge of the situation told the Tribune.
His death has been ruled a suicide, but the Miami-Dade police department has yet to make the information public.
Foul play was ruled out, in part because no one but Duerson was seen entering his condominium for two days before the shooting.
The 50-year-old was found dead Thursday night in his Miami home.
Chris Nowinski, co-director of the Center for the Study of Traumatic Encephalopathy at Boston University School of Medicine, said Duerson's family contacted him to examine Duerson's brain for abnormalities related to chronic traumatic encephalopathy (CTE), a degenerative brain disease found in those who have a history of repetitive brain trauma, including concussions.
Photo: Bears safety Dave Duerson. (Tribune file photo)
"He had informed (his family) at some point that he wanted his brain to be studied so people could learn more about the effect of brain trauma and so kids could play the game more safely in the future," Nowinski said.
"The family requested that I confirm that Mr. Duerson's brain was donated to our research center, and it was Mr. Duerson's wishes."
Nowinski also said the family provided the appropriate release forms so the brain could be studied, a process that should take between three to six months.
"NFL players are at higher risk for CTE than normal people and probably other athletes as well," Nowinski said. "Of the 14 former NFL players we've completed studies on, 13 of them had the disease."
Nowinski, who grew up in Arlington Heights and played football at Hersey High, said he met Duerson in 1996 when Duerson presented Nowinsky with a National Football Foundation Scholarship.
"I was a great admirer of Mr. Duerson as a player," he said. "It was a thrill just to meet him and have my picture taken with him."
The Bears selected Duerson out of Notre Dame in the third round of the 1983 draft. He became a starter in 1985 and played in the first of four consecutive Pro Bowls that season. In 1987, he was named the Walter Payton NFL Man of the Year. He also was one of the Bears' NFLPA representatives and was a leader through the 1987 strike.
More Chicago safety shot himself; brain to be studied