The San Diego County Coroner has ruled former longtime NFL linebacker Junior Seau's death a suicide.
Seau, 43, was found dead of a self-inflicted gunshot wound of the chest Wednesday morning at his Oceanside, Calif., home, according to a news release.
His body will be released to the family's mortuary after "completion of administrative responsibilities in the death certificate."
Officials conducted a forensic autopsy, which includes "a full examination of a decedent's body and organs and collection of specimens for laboratory studies."
The Medical Examiner's Office is "awaiting the family's decision regarding study of the brain for repetitive injury by researchers outside of the office," the coroner's release said.
At a press conference outside Seau's home on Wednesday, Oceanside Police Chief Frank McCoy said a woman who identified herself as Seau's girlfriend called 911 at 9:45 a.m. PT and told the dispatcher she had found Seau unconscious in a bedroom with a gunshot wound to the chest.
McCoy said a handgun was found near Seau's body.
Seau played in the NFL for 20 years for the San Diego Chargers, Miami Dolphins and New England Patriots.
His death bears a resemblance to that of other athletes, including Chicago Bears football player Dave Duerson, who shot himself in the chest in February of 2011. Duerson left a note requesting his brain be sent to the "NFL brain bank" for study.
Police did not find a suicide note from Seau, but the former all-star athlete reportedly texted, "I love you," to his ex-wife and three children, and canceled an afternoon photo shoot with the U-T San Diego newspaper, saying he didn't feel well, according to ABC News' Los Angeles affiliate, KABC.
Sports Illustrated reported Thursday that the Boston University's Center for the Study of Traumatic Encephalopathy requested to study Seau's brain, but the magazine later noted that the center attempts to examine the brains of all athletes who die after being involved in hard-hitting sports.
Gina Digravio, a media relations manager with the BU Center, told ABCNews.com that the center has not and will never discuss the details of which brains the researchers are studying or plan to study.
Several former NFL players have committed suicide in recent years, and many experts believe the deaths could be related to repeated blows to the head. In addition to Duerson, ex-Pittsburgh Steelers offensive lineman Terry Long and Philadelphia Eagles defensive back Andre Waters took their own lives.
Chronic traumatic encephalopathy, or CTE, a degenerative and progressive disease found in people who have experienced multiple blows to the head, has shown up in the brains of several former athletes who committed suicide, including Duerson.
The average life expectancy of a retired football player is 58 years, according to the NFL Players Association. That stands in contrast to the average American man's life expectancy of 75 years, according to government data based in 2006.
People close to Seau said the former player suffered several concussions during his career, although he was never listed on any NFL injury report as having a concussion, according to ESPN.