A post-mortem on Michael Jackson has revealed there are no signs of external injury to the superstar’s body.

The preliminary findings of the three-hour examination were released by the Los Angeles County Coroner late yesterday.

The exact cause of death for the 50-year-old may not be known for another six weeks as medics await toxicology reports.

Police and the coroner’s officials are currently investigating the role prescription drugs played in Jackson’s death amid claims he was injected with the powerful morphine-like painkiller Demerol shortly before his death.

Entertainment news website TMZ, which broke the story of Jackson’s demise, claims the singer received an injection of painkillers at 11.30am the day of his death.

Later that afternoon the singer was pronounced dead at the UCLA medical centre.

Family lawyer Brian Oxman has said he was concerned about the star's use of pain relief medication as Jackson was dogged by rumours of prescription drug addiction in the latter half of his life.

Speaking outside the coroner’s office late yesterday a spokesman said: “The medical examiner has ordered additional testing such as toxicology and other studies. The cause of death has been deferred.”

He added: “There was no indication of any external trauma or indication of foul play to the body of Mr. Jackson.”

Police have put a security on Jackson’s case limiting the amount of information that can be released.

After pathologists had finished with the singer’s body, taking blood samples for further tests, it was released to the family.

Jackson’s remains were quietly taken to an undisclosed mortuary late on Friday night evading a crowd outside the coroner’s.

Plans for the star’s funeral have yet to be disclosed by the family.

It is thought it could take place in his home town of Gary Indiana, an industrial suburb of Chicago where Jackson, who was raised as a Jehovah’s Witness, grew up with his siblings.

LA police are still seeking to question Jackson’s personal physician, identified by news media as Houston-based cardiologist Dr. Conrad Murray who was with him on the day of his death.

Both Jackson's ex-wife Lisa Marie Presley and a friend, Deepak Chopra, have both voiced concerns over the level of prescription drugs the one-time child prodigy took.

Californian-based writer Deepak Chopra, claimed the singer approached him in a bid to get prescription drugs after his trial on child abuse charges.

He told Sky News: “In 2005 he asked me for a prescription and that’s when I started to get curious about whether he was taking prescription medications and narcotics and the more I probed the more he denied it, but then he admitted he was taking a lot of prescription medication for pain.” He said Jackson asked for a particular drug Oxycontin.

Writing on her MySpace page the daughter of Elvis Presley said Jackson feared he would meet his end in a similar manner to her father who died in 1977 of a suspected drugs overdose.

Ms Presley recalled a conversation where Jackson said: "’I am afraid that I am going to end up like him, the way he did,’", referring to her father. She went on to say she was “overwhelmed” by the loss of ex-husband Jackson

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