Junior Seau before the start of the 2010 AFC Wild Card playoff game.
TAMPA, Florida -- Published reports indicate former NFL star Junior Seau suffered from a brain disease, likely caused by two decades worth of blows to the head, when he killed himself last May.
The former all-pro ended his life at his California home with a gunshot to the chest. According to The Sports Network, many believed he shot himself in the chest to preserve his brain for testing; his family members donated it to neuroscientists at the National Institutes for Health.
According to a report from ABC News and ESPN, researchers have concluded that Seau suffered from chronic traumatic encephalopathy (CTE), a degenerative disease typically caused by multiple hits to the head.
In November, the 10 News Investigators reported on the NFL's "concussion crisis" - a growing number of suicides including Seau, Tampa resident Andre Waters, Tampa native O.J. Murdock, and former Buccaneers lineman Tom McHale.
Also spotlighted was new research on CTE - a disease which kills portions of the brain. Some doctors are now recommending kids avoid all contact sports until the age of 14.
Seau, who was just 43 years old when he died, was known as one of the hardest-hitting linebacksers during his 20 NFL seasons. He spent 13 years with San Diego, three with Miami and four with New England before retiring after the 2009 season.
Charges retire Junior Seau's number at memorial service
The 12-time Pro Bowl selection is just the latest former NFL player believed to have CTE, which can only be ascertained after death.
Former NFL defensive back Dave Duerson, who played with the Chicago Bears, New York Giants and Arizona Cardinals, also killed himself in 2011 and was found to have CTE. He asked his family to donate his brain for testing.
The Seau report could also be another blow to the NFL in its ongoing issues with concussions and brain disease.
Seau's suicide focuses attention on concussions
Numerous lawsuits have been filed against the league by former players who have alleged the NFL knew about the dangers of concussions and other head injuries, but did nothing to protect the players.
NFL commissioner Roger Goodell has made player safety among his chief concerns in recent years.
Find 10 News Investigator Noah Pransky on Facebook or follow his updates on Twitter. Read his Sports Business Blog at Shadow of the Stadium.
More Junior Seau stories...
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Materials from The Sports Network were used in this report