TMZ first reported that the 43-year-old was found dead and that cops are currently investigating a shooting. It later confirmed earlier reports that his death was the result of a self-inflicted gunshot wound.
North County Times reported that his death was caused by a self-inflicted wound to his chest. It said that the mayor of Oceanside, where Seau lived, learned from the chief of police that Seau had killed himself.
The suicide is reminiscent of former Chicago Bears' player Dave Duerson killing himself last year with a self-inflicted gunshot wound to the chest. Duerson's reasoning was to have his brain examined after years of concussions and physical abuse from playing in the NFL.
Seau leaves behind his ex-wife and three children. He reportedly sent text messages to them on Tuesday, telling them he loved them; however, they reportedly didn't think anything of it.
Seau was a 12-time Pro Bowler during his 20 seasons in the NFL with the San Diego Chargers, Miami Dolphins, and New England Patriots. He was known as one of the hardest-hitting linebackers in the sport and a popular player.
According to TMZ, he was involved in a 2010 car crash that some speculated was a suicide attempt, but the former NFL player said that he wasn't trying to kill himself and had fallen asleep at the wheel.
He's the eighth member of the 1994 San Diego Chargers' Super Bowl team to pass away.