July 2, 2009 -- "Kung Fu" actor David Carradine died from asphyxiation, according to New York-based medical examiner Dr. Michael Baden, who was hired by the family to do a private autopsy on the actor.
Baden, the host of HBO's "Autopsy" series, ruled out suicide because of the way the actor's body was bound. He has not yet rule out homicide or autoerotic asphyxiation, which many had speculated was the cause of death.
Carradine was found June 4 hanging in the closet of his Bangkok hotel room. Until now, details on autopsies here and in Thailand have been scant. Thai authorities said their report would take at least a month.
Baden stressed that his full determination of how Carradine died will not be ready until at least a week.
"The cause of death was asphyxiation, an inability to breathe, now, why that happened is still what we're working on," Baden told Reuters today.
He also said the ligatures, or ropes, that bound Carradine's body at the time of death ruled out suicide. The family had insisted the actor was happy working on a film at the time of his death and would not have taken his own life.
"He didn't die of natural causes, and he didn't die of suicidal causes from the nature of the ligatures around the body, so that leaves some kind of accidental death," Baden said.
Thai authorities had suggested the 72-year-old actor could have died from accidental autoerotic asphyxiation. In response to a question on that topic, Baden did not rule out that possibility, but he also did not say autoerotic asphyxiation was the cause.
Contradicting media reports saying Carradine's hands were tied behind his back, Baden told Reuters the actor's hands were above his head.
The Carradine family had no comment after the autopsy report.
Baden said he was waiting for more information on the hotel pass keys and security video to determine if, as the family had suggested, the death was a homicide.
"It takes time to finish a case sometimes, so it's not unexpected," he said.
After the actor's death, Keith Carradine called his brother's death a "devastating loss" for his family and thanked fans for their "compassion."
Brother Robert Carradine added, "Until we have all of the pending results of the investigation we respectfully ask that we be allowed to lay our beloved brother, husband and father, grandfather and great-grandfather to rest in peace and with dignity.
"Once the investigation is fully completed and definitive conclusions have been reached, we will address the findings with the public," Robert Carradine added. "Thank you for your understanding during this profoundly painful time."
A grainy photo of his limp body in a Bangkok hotel room -- in what appears to be fishnet and a wig -- raised more questions about his mysterious death.
The photo, which was printed in the tabloid Thai Rath, shows Carradine's body suspended from a bar in a closet.
Police said he was found with his hands bound together above his head and rope around his neck and genitals. Nearby on a bed is what appears to be red women's lingerie.
Transvestite fetishes and thrill-seeking can be an integral part of auto-erotic asphyxia, the deadly sex play that Thai authorities said killed the 72-year-old former "Kung Fu" actor.
But these new details also add fuel to the Carradine family's claims that the actor may have been the victim of a homicide. His body was found hanging by ropes in a closet June 4 in a Bangkok hotel.
And while Thai authorities have ruled the actor's death as a sex play accident -- auto-erotic asphyxia gone wrong -- some say the evidence just doesn't add up.
"The thing that I am really questioning is, how was he bound, and how was he able to tie his own hands?" said Robert Dunlap, who interviewed hundreds of people who practice deviant sex behaviors for his 2002 documentary film, "Beyond Vanilla: An Unforgettable Journey Into the Wilder Side of Sex."
"This doesn't look like a solo act at all," he told ABCNews.com. "In order to have an orgasm, his hands would have had to be free. There is something very peculiar about this."
"You don't dress just for yourself," he said of the photos that revealed women's clothing. "Usually there is some sort of show and someone else is involved. It probably went horribly bad and they left."
Carradine's manager Chuck Binder has publicly echoed his own concerns.
How Do You Do It Yourself?
"How do you get a rope around your neck and around your genitals and do all this by yourself?" Binder asked. "My take is there was definitely foul play. There's a lot of weird stuff that happens in Bangkok. This isn't L.A. or New York."
With funeral plans still on hold, the family hired Baden, a renowned New York forensic expert, who flew to Los Angeles Monday to conduct a new investigation. Funeral plans have yet to be announced.
"If this act was for pleasure, I can tell from the ligature," Baden told columnist Cindy Adams. "Some cloth would've hidden the rope mark around his neck so that it wouldn't show next day. I'll have to see the photos before they cut him down."
Mark Geragos, attorney for the actor's half-brother, Keith Carradine, even suggested on last week's "Larry King Live" that a Kung Fu secret society could be to blame.
But Carradine's fourth wife, Marina Anderson, told the New York Post, "If he was involved in secret societies, it was a secret that even I didn't know about. But he did have some big secrets."
Those secrets, according to at least two of Carradine's four ex-wives, included a passion for deadly sex play.
His third wife, Gail Jensen, told RadarOnline that he liked to tie himself up, had a fetish for Speedos and often experimented with nearly drowning himself in the pool.
In another interview with TMZ, Jensen says that Carradine had hung himself up in the basement in a crucifix position, mimicking Jesus Christ, while a party was going on upstairs.
"David was pretty strange," she said. "He would like to get tied up. He would tie himself up and I would walk in and see him and say, 'Oh, my God, David, you got to be kidding me -- and I would (turn around and) walk out. I would leave him to his own devices."
Jensen, who was divorced from Carradine in 1997, added, "He liked to be tied up. And he could tie himself up ... He spent days planning a different feature. He would go to a hardware store and buy the stuff."
"It was never sexual," she said, noting that Carradine liked bondage but never choked himself.
Anderson, his fourth wife, told ABCNews.com that her claims in her 2003 divorce papers that he practiced "deviant" and "dangerous" sex behavior, including incest, were true.
Carradine was married five times and has five daughters and two sons.
But according to Dr. Martin Kafka, clinical associate professor of psychiatry at McLean Hospital in Belmont, Mass., all that has been reported on Carradine's body is consistent with auto-erotic asphyxia.
"[It] is often associated with sexual masochism -- sexual arousal to bondage/restraints, pain and humiliation, such as bound hands and testicles, and transvestic fetishism, such as women's clothing and undergarments and dildoes if they were present," said Kafka.
As for how one reaches orgasm with hands tied behind the back, he noted that anoxia -- severe oxygen deprivation -- alone can be associated with orgasm.
But, he added, who has nothing to do with the Carradine investigation, "I do not know if that is fact or fiction."
According to forensic psychiatrist Stephen Hucker of the University of Toronto, auto-erotic asphyxia is also associated with mood disorders, and in 60 percent of cases, patients had made previous attempts to take their lives.
Though Carradine's ex-wife Anderson said he was "always happy when he was working," he reportedly suffered from bouts of depression and had written about suicide.
He also abused alcohol, according to Anderson, who was credited with sobering up the actor for his role in "Kill Bill."
Even though the family has said Carradine was happy at the time of his death, working on the movie "Stretch," experts say many who practice this deadly sex act have other mental issues.
Admiring the act itself is also a hallmark of the deadly practice.
"Sometimes a mirror will have been placed strategically near the body to allow the subject to view himself as he performs his ritual, or a camera may have been set up so that the person may photograph or videotape himself," according to Hucker. "Others will create an entire environment that relates to some special fantasy and may involve, for example, the creation of a torture chamber or other obviously sadomasochistic theme."
Besides mirrors, sexual paraphernalia can include self-photography, bondage, hoods, blindfolds, enemas, electrical stimulation and beating of self or by a partner.
Because auto-erotic asphyxia is so "heavily stigmatized, by its very nature practitioners lead a hidden life," said Kafka.
"That [Carradine] had a substance abuse problem or had suicidal thoughts is not all that surprising," he told ABCNews.com. "That would make sense."
Even after the investigation of Carradine's death is complete, it still may be difficult to determine if it was an accident, a suicide or even a murder.
"It's hard to know their intention because we can't ask them," Kafka said.
The Associated Press contributed to this report.