David Carradine's family fear he was murdered to silence his investigation into deadly underground martial arts organisations.
The actor was found hanging in a hotel room in Bangkok, Thailand on Thursday, at the age of 72.
His family is waiting for the official cause of death - but they refuse to acknowledge he may have committed suicide or died taking part in a dangerous sex game.
Instead they want America's Federal Bureau Of Investigation (FBI) to probe the possibility he was killed by assassins.
During an appearance on Larry King's talk show on Friday lawyer Mark Geragos revealed Carradine was investigating secret kung fu societies, whose members had the motive and means to kill him.
When the topic was raised by a panelist on the show, Geragos responded, "Absolutely. What that means is connected to martial arts and his interest in martial arts. So there is a suspicion of foul play. That may be the first area where they should look."
But his ex-wife Marina Anderson disputes the suggestion, telling the New York Post, "If he was involved in secret societies, it was a secret that even I didn't know about."
WENN.com