Thai police said on Monday that the cause of U.S. actor David Carradine's death in a Bangkok hotel room would not be known until they had the results of the autopsy and toxicology tests in a month's time.

The police refused to give further details about their investigation into the 72-year-old actor's mysterious death, amid intense media speculation about causes ranging from suicide to murder via accidental autoerotic asphyxiation.

"We are still investigating but we will not make any assumptions about his death until we have gathered all the facts," the deputy Bangkok police chief, Lieutenant-General Amnoy Nimmino, told a news conference.

"We have to wait for the toxicology reports, the result of the autopsy and forensic evidence. We will know everything in one month."

Carradine, the star of U.S. 1970s show "Kung Fu," was filming the movie "Stretch" in the Thai capital when a maid found him dead in his suite at the plush Swissotel Nai Lert Park on June 4.

The police also refused to confirm the authenticity of a grainy photo published by a tabloid-style Thai newspaper, which said it was of Carradine's naked, hanging body.

Carradine's family said it was "profoundly disturbed" by the photo, printed on Saturday in the Thai Rath newspaper, and threatened legal action, the actor's brother, Keith Carradine, said in a statement issued by lawyer Mark Geragos.

"The family wants it understood that ... any persons, publications or media outlets will be fully prosecuted for invasion of privacy and causing severe emotional distress if the photos are published," the statement said.

Thai Rath, the country's top-selling newspaper, is known for its lively coverage of crime and celebrities. It did not give a source for the photograph and the face could not been seen.

"I cannot say anything about this photograph," said Amnoy. "The media were not present at the crime scene and this picture was not leaked by the police."

Initial police reports said the actor had committed suicide, but relatives insisted Carradine would not take his own life.

Thai police and media then speculated that accidental autoerotic asphyxiation was a possible cause of death.

The Thai coroner has said it could be several weeks before the results of the toxicology tests and autopsy are known.

Carradine's family called on U.S. authorities on Saturday to help explain how he died, and a U.S. embassy official in Bangkok said the Federal Bureau of Investigation (FBI) was discussing the case with Thai police.

Amnoy said the FBI was welcome to take part in the investigation, but only after Thai prosecutors had received a formal request from the U.S. government.

Carradine's family has hired a forensics pathologist to examine the actor's body, which was flown home to Los Angeles on Saturday

Source: REUTERS