Los Angeles coroners found lethal levels of the anaesthetic propofol in the body of Michael Jackson after his death, the Los Angeles Times reported on its website Monday.
The report cited a search warrant for the premises of Jackson's doctor Conrad Murray, which was unsealed Monday in Houston, Texas.
The search warrant quoted Murray, 50, as saying that he had treated Jackson for insomnia for six months using propofol, regularly giving him 50 milligrams of the drug via an intravenous feed. But he also claimed that he had been trying to wean the pop star off the powerful drug and on the day he died, Jackson only received a 25-milligram dose.
Propofol is usually used only as a hospital anesthetic and the discovery of lethal levels in Jackson's system is likely to increase speculation that Murray will face charges over the June 25 death of the pop star.