The 72-year-old was found dead by a maid in a Bangkok hotel room on Thursday. He was discovered hanging naked in a wardrobe with ropes tied around his neck and genitals.
Speaking to reporters, Thai Police Lt. Gen. Worapong Chrewprecha said: "The two ropes were tied together. It is unclear whether he committed suicide or not or he died of suffocation or heart failure due to an orgasm."
He added that production crew told police that Carradine had been drinking beer "from morning until evening the day before he was found dead".
The results of an autopsy completed earlier today have yet to be released - however, officials have speculated that the cause of death might have been accidental suffocation.
Friends and family of the star were quick to dismiss early speculation that he had taken his own life, with his personal manager saying: "He really appreciated everything life has to give...and that's not something David would ever do to himself."
She added that he was "in good spirits" when he left for Thailand on May 29 and was looking forward to starting work on Stretch.
Carradine rose to fame as the martial arts expert Kwai Chang Caine in the Kung Fu series. He went on to appear in over one hunded films, including the recent Quentin Tarantino saga Kill Bill.
He is survived by his wife and four children.