The Los Angeles County coroner's finding that the death of Michael Jackson was a homicide could mean criminal charges for his doctor, who told investigators that he administered a mix of powerful drugs to treat the pop star's insomnia hours before his death.

The homicide ruling was based on forensic tests that found the anesthetic propofol combined with at least two sedatives to kill Jackson, a law enforcement official told The Associated Press on Monday.

While the finding does not necessarily mean a crime was committed, it means more likely that criminal charges will be filed against Dr Conrad Murray, the Las Vegas cardiologist who was caring for Jackson when he died on June 25 in a rented Los Angeles mansion.

Through his lawyer, Murray has said he administered nothing that "should have" killed Jackson.

Addiction feared

Murray told investigators that at the time of the King of Pop's death, he had been trying to wean Jackson off propofol.

The doctor said he'd been treating Jackson for insomnia for about six weeks with 50 milligrams of the drug every night via an intravenous drip, a search warrant affidavit said.

Murray said he feared Jackson was becoming addicted to the anesthetic, which is supposed to be used only in hospitals and other advanced medical settings.

The affidavit unsealed in Houston, where Los Angeles police took material from one of Murray's clinics last month as part of their manslaughter investigation, includes a detailed account of what detectives say Murray told them. Manslaughter is homicide without malice or premeditation.

Murray told detectives that he had lowered the propofol dose to 25 milligrams and added the sedatives lorazepam and midazolam two days prior to Jackson's death, a combination that succeeded in helping the pop star sleep.

The next day, Murray said, he cut off the propofol - and Jackson fell asleep with just the two sedatives.

Drug cocktail

But on June 25, Murray said he tried unsuccessfully to make Jackson sleep with a series of drugs that included a 10-milligram tablet of Valium and repeated injections of two milligrams of lorazepam and two milligrams of midazolam.

When they didn't work, he gave in to Jackson's "repeated demands/requests" for propofol, according to the affidavit. Murray administered 25 milligrams - a relatively small dose - and finally, Jackson fell asleep. Murray remained with the sedated Jackson for about 10 minutes, then left for the bathroom, the affidavit said. Less than two minutes later, Murray returned and found Jackson had stopped breathing.

It is no surprise that such a combination of medications could kill someone, said Dr David Zvara, anesthesia chairman at the University of North Carolina at Chapel Hill.

"All those drugs act in synergy with each other," Zvara said. Adding propofol on top of the other sedatives could have "tipped the balance" by depressing Jackson's breathing and stopping his heart.

(Shanghai Daily/Agencies August 26, 2009)