Michael Jackson's family gathered at his parents' suburban Los Angeles home to make funeral arrangements for the troubled King of Pop amid reports that they are seeking a second, independent autopsy.

Jackson's body was returned to his family on Friday night after an examination by the Los Angeles County coroner's office failed to determine what killed the 50-year-old entertainer, pending toxicology tests that were expected to take four to six weeks.

Members of Jackson's family were said to be gathering at his parents home in suburban Los Angeles to plan a funeral for the "King of Pop," whose sudden death on Thursday dominated worldwide headlines and touched off two days of tributes from fans.

No funeral plans have been disclosed to the public.

Coroner's officials have said that with no outward signs of trauma to Jackson's body or evidence of foul play, they would have to wait for the results of toxicology tests and other studies to establish a cause of death.

Speculation has centered on Jackson's use of prescription drugs and reports that he was injected with the narcotic painkiller Demerol shortly before collapsing at his rented mansion in a Holmby Hills neighborhood of Los Angeles.

The 50-year-old entertainer was in full cardiac arrest when paramedics arrived, with his personal physician, identified as Dr. Conrad Murray, trying desperately to revive him.

Celebrity website TMZ.com, citing an interview with an unidentified "close member" of the Jackson family, has reported that the entertainer was injected with Demerol about half an hour before he went into cardiac arrest.

TMZ, citing family members, said Jackson received a daily shot of Demerol, a narcotic painkiller, and that the family believed his death was caused by an overdose of the drug.

A senior law enforcement official told ABC News that Jackson was "heavily addicted" to the painkiller Oxycontin and was injected daily with that medication, along with Demerol.

Meanwhile a lawyer for Dr. Conrad Murray, who was at Jackson's rented mansion in the Holmby Hills neighbourhood of Los Angeles when he collapsed, said the physician had agreed to answer questions from police detectives.

Police towed Murray's silver Mercedes from the driveway of the home where Jackson died, saying they wanted to search it for evidence and medication, and have sought to arrange further interviews with the Houston-based cardiologist.

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