NFL legend Junior Seau was found dead in his Oceanside, CA ... and cops are investigating a shooting ... multiple sources tell TMZ.
Cops are currently at Seau's home just outside San Diego. Seau was 43-years-old ... and leaves behind 3 kids and an ex-wife.
Seau was a beast in the NFL -- skyrocketing to fame thanks to his explosive play with the San Diego Chargers, Miami Dolphins and New England Patriots. The USC standout was selected in the first round of the NFL draft in 1990 and played in the league for 20 years.
Seau was involved in a back in 2010 when he drove his SUV off a cliff in Carlsbad, CA hours after he was for allegedly attacking his girlfriend. Seau later said he was not trying to kill himself ... insisting he had fallen asleep at the wheel.