Speculation continues to swirl around the death of actor David Carradine.
Early police statements pegged the 72-year-old's death Wednesday in Bangkok, Thailand as a suspected suicide.
But a Thai forensic scientist said Friday that Carradine may have died attempting a sex act known as auto-erotic asphyxiation, while a rep for the actor told TMZ that the family was told by Thai authorities that Carradine's hands were tied behind his back, and so suspect foul play.
The "Kill Bill" star's body was discovered Thursday in his luxury suite at Bangkok's Swissotel Nai Lert Park Hotel. Police Lt. Gen. Worapong Chewprecha told reporters that Carradine was found with a rope "tied around his penis and another rope around his neck."
"The two ropes were tied together," he said. "It is unclear whether he committed suicide or not or he died of suffocation or heart failure due to an orgasm."
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Pornthip Rojanasunand, director of Thailand's Central Institute of Forensic Science, said Carradine may have died attempting auto-erotic asphyxiation -- cutting off oxygen to the brain for sexual arousal.
The practice is said to result in a form of giddiness and euphoria -- similar to alcohol or drug intoxication -- that enhances the sexual experience.
"If you hang yourself by the neck, you don't need so much pressure to kill yourself. Those who get highly sexually aroused tend to forget this fact," Pornthip said.
Thai police completed an autopsy on Carradine Friday but so far have not released the results. Carradine's body was also transported back to the U.S. on Friday, TMZ reports.
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Dr. Nanthana Sirisap, director of Chulalongkorn Hospital's Autopsy Center, told reporters that the autopsy was conducted because of the "unusual circumstances surrounding Carradine's death," but he did not elaborate.
Police Lt. Teerapop Luanseng had said on Thursday that Carradine's body was found "naked, hanging in a closet," and that police at the time suspected suicide.
"All we can say is, we know David would never have committed suicide," said Tiffany Smith of Binder & Associates, his management company. "We're just waiting for them to finish the investigation and find out what really happened. He really appreciated everything life has to give ... and that's not something David would ever do to himself."
One of Carradine's managers, Tiffany Smith of Binder & Associates, dismissed initial suicide reports.
"All we can say is, we know David would never have committed suicide," said Tiffany Smith, of Binder & Associates, his management company. "We're just waiting for them to finish the investigation and find out what really happened. He really appreciated everything life has to give ... and that's not something David would ever do to himself."
Chuck Binder, Carradine's manager, said the actor was staying in the Thai capital while shooting a movie called "Stretch." When a producer went to his luxury hotel room, he learned that the actor was dead, Binder said.
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According to Thai Newspaper, The Nation, Carradine had been staying at the hotel since Tuesday but could not be contacted after he failed to appear for a meal with the rest of the film crew on Wednesday.
It said a preliminary police investigation found that he had hanged himself with a cord used with the room's curtains. It cited police as saying he had been dead at least 12 hours and there was no sign that he had been assaulted.
A statement on behalf of his family has yet to be released, but Binder called the death "shocking and sad ... He was full of life, always wanting to work ... a great person."
But despite an enthusiasm for his work, the actor had openly discussed his battle with suicidal thoughts. In a 2004 interview, Carradine said: "I remember one time sitting at the window of the third or fourth floor of the Plaza Hotel for about an hour, thinking about just tipping off."
He also said he had considered shooting himself.
"Look, there was a period in my life when I had a single action Colt 45, loaded, in my desk drawer. And every night I'd take it out and think about blowing my head off, and then decide not to and go on with my life. Put it back in the drawer and open the laptop and continue writing my autobiography or whatever. But it was just to see."
The actor is survived by his wife Annie Bierman and three children.
Carradine was a leading member of a venerable Hollywood acting family that included his father, character actor John Carradine, and brother Keith.
In all, he appeared in more than 100 feature films with such directors as Martin Scorsese, Ingmar Bergman and Hal Ashby.
One of his prominent early film roles was as singer Woody Guthrie in Ashby's 1976 biopic "Bound for Glory."
But he was best known for his role as Kwai Chang Caine, a Shaolin priest traveling the 1800s American frontier West in the TV series "Kung Fu," which aired in 1972-75.
He reprised the role in a mid-1980s TV movie and played Caine's grandson in the 1990s syndicated series "Kung Fu: The Legend Continues."
He returned to the top in recent years as the title character in Quentin Tarantino's two-part saga "Kill Bill."
The character, the worldly father figure of a pack of crack assassins, was a shadowy presence in 2003's "Kill Bill — Vol. 1." In that film, one of Bill's former assassins (Uma Thurman) begins a vengeful rampage against her old associates.
In "Kill Bill — Vol. 2," released in 2004, Thurman's character comes face to face again with Bill himself. The role brought Carradine a Golden Globe nomination as best supporting actor.
Bill was a complete contrast to his TV character Kwai Chang Caine, the soft-spoken refugee from a Shaolin monastery, serenely spreading wisdom and battling bad guys in the Old West. He left after three seasons, saying the show had started to repeat itself.
After "Kung Fu," Carradine starred in the 1975 cult flick "Death Race 2000." He starred with Liv Ullmann in Bergman's "The Serpent's Egg" in 1977 and with his brothers in the 1980 Western "The Long Riders."
But after the early 1980s, he spent two decades doing mostly low-budget films. Tarantino's films changed that.
"All I've ever needed since I more or less retired from studio films a couple of decades ago ... is just to be in one," Carradine told The Associated Press in 2004.
"There isn't anything that Anthony Hopkins or Clint Eastwood or Sean Connery or any of those old guys are doing that I couldn't do," he said. "All that was ever required was somebody with Quentin's courage to take and put me in the spotlight."
One thing remained a constant after "Kung Fu": Carradine's interest in Oriental herbs, exercise and philosophy. He wrote a personal memoir called "Spirit of Shaolin" and continued to make instructional videos on tai chi and other martial arts.
In the 2004 interview, Carradine talked candidly about his past boozing and narcotics use, but said he had put all that behind him and stuck to coffee and cigarettes.
"I didn't like the way I looked, for one thing. You're kind of out of control emotionally when you drink that much. I was quicker to anger."
"You're probably witnessing the last time I will ever answer those questions," Carradine said. "Because this is a regeneration. It is a renaissance. It is the start of a new career for me.
"It's time to do nothing but look forward."
The Associated Press contributed to this report.