An expert on the powerful anaesthetic blamed for Michael Jackson’s death hinted he disagreed with the prosecutors’ theories in the case against the singer’s personal doctor.

Paul White, a medical doctor, was testifying for Conrad Murray, who has denied involuntary manslaughter in Jackson’s death in 2009.

Dr White said he reviewed reports by more than a dozen experts and would not expect Michael Jackson to have died from the drugs that Dr Murray told police he gave the singer.

Dr Murray was giving Jackson the anaesthetic propofol as a sleep aid.

A prosecution expert says Dr Murray probably gave Jackson propofol at a higher dose than he told police, then left the room.

Dr White said he could not justify the conduct if that happened, but he is expected to present an alternative theory.

The Day before lawyers for Dr Murray had sought to shift blame to another doctor and a different drug, calling addiction expert Robert Waldman to say Michael Jackson, 50, was hooked on Demerol in the months before his death.

They suggested the singer’s withdrawal from the painkiller triggered the insomnia that Dr Murray was trying to resolve when he gave Jackson propofol.

Dr Murray’s lawyers claim the ultimate blame lies with Michael Jackson himself, but they also sought to implicate his dermatologist in the drug-laced path to his death.

Dr White said he was “perplexed” after reading documents in the case about whether Dr Murray administered the propofol dose that killed Michael Jackson.

He noted that Dr Murray described to police a very low dose of the drug. If that was true, Dr White said: “I would not have expected Michael Jackson to have died.”