Michael Jackson's family say they are angry and frustrated over unanswered questions surrounding his death and may seek a second post mortem.Speaking to ABC television's Good Morning America, US activist Reverend Jesse Jackson said he had spent time comforting the family at their estate in northern LA.
He said they have concerns with the late singer's personal doctor, who was with the 50-year-old when he died on Thursday.
LA police have already spoken to cardiologist Conrad Murray and say they intend to interview him a second time.
A post mortem completed by the LA coroner has ruled out foul play, but revealed Jackson had been taking some unspecified prescription medications.
Asked if the family would seek their own post mortem, Rev Jackson replied: "I'm sure they ought to, they probably will."
The comments were followed soon after by an internet report which said LA police wanted to speak to a second person in connection with Jackson's death.
Showbiz website TMZ.com said police wanted to talk to Dr Tohme Tohme about an "alleged indirect connection" between prescription drugs and the pop singer's demise, according to their sources.
However, LAPD officer Norma Eisenman denied knowing anything about the report.
TMZ quotes Dr Tohme who as saying to them: "I don't have anything to do with his (Michael's) medication or health... Why should I talk to police?"
Sky correspondent Greg Milam, who is in LA, says Dr Tohme was one of many doctors that cared for Jackson.
"It is a name that has been in the Michael Jackson circle for a number of years - one of the many in the entourage - and nobody really knew what they were up to and what role they fulfilled," he said.
"Clearly police have a responsibility to investigate and will want to speak to everyone who has something to shed on that picture... the minute he was removed from his home and died in hospital."
The singer's body has been released to his family, but further toxicology tests have been ordered, which could take several weeks to be completed.
LA Police Department assistant police chief Charlie Beck said further tests would provide "key results that will steer the direction of the investigation".
No funeral plans have been announced, but the Jackson family say they have not ruled out a public event.
Speculation over the music icon's death is being fuelled by reports Jackson had been receiving a daily injection of Demerol, a synthetic narcotic similar to morphine, and may have been given "too much" on the day he died.
Earlier reports said the Jackson family had been concerned over pop star's use of drugs as he prepared for a series of comeback concerts in London.
Physician and Jackson confidante, Dr Deepak Chopra, told CNN bluntly: "I think drugs killed him."
Thoughts have also turned to the pop singer's three children, who are currently being cared for by Jackson's mother.
But reports have emerged of a possible custody battle with Debbie Rowe, biological mother to Jackson's two eldest children.