UPDATED: Coroner Rules Jackson's Death Homicide, Murray Lied To Police

LOS ANGELES — 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, speaking on condition of anonymity because the findings have not been publicly released.

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 June 25 in a rented Los Angeles mansion.

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

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 materials 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.

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, which the singer called his "milk," according to the affidavit. Murray administered 25 milligrams of the white-colored liquid – 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.

Cell phone records show three separate calls from Murray's phone for between 11:18 a.m. and 12:05 p.m., the affidavit said. It's not clear who received the calls. Murray had told authorities he was administering CPR during that time.

In a statement posted late Monday on his firm's Web site, Murray's attorney Edward Chernoff questioned the timeline as depicted in the affidavit, calling it "police theory."

"Dr. Murray simply never told investigators that he found Michael Jackson at 11:00 a.m. not breathing," Chernoff said. He declined to comment on the homicide ruling, saying, "We will be happy to address the coroner's report when it is officially released."

The coroner's office has withheld its autopsy findings, citing a request from police to wait until their investigation is complete.

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 ultimately stopping his heart.

The 25 milligrams of propofol "is not a whopping amount," said Lee Cantrell, director of the San Diego division of the California Poison Control System. It was the cocktail of the other sedatives, known as benzodiazepines, that "may have been the trigger that pushed him over the edge," Cantrell said.

"This is horrible polypharmacy," he said, referring to the interaction among the various drugs. "No one will treat an insomniac like this."

The affidavit, signed by a judge July 20, said that the coroner's office chief medical examiner told police his review of preliminary toxicology results showed "lethal levels of propofol."

Besides the propofol and two sedatives, the coroner's toxicology report found other substances in Jackson's system but they were not believed to have been a factor in the singer's death, the official told the AP.

Murray didn't tell paramedics or doctors at the UCLA hospital where Jackson was rushed about any drugs he administered other than lorazepam and flumazenil, a "rescue drug" to counteract problems from too much lorazepam, according to the affidavit.

It was only during a subsequent interview with Los Angeles Police detectives that Murray gave a more full accounting of the events leading up to the 911 call, the document said.

A call to the coroner's office was not returned Monday. A spokeswoman for the Los Angeles District Attorney's said no case had been presented so the office had nothing to comment on.

The line between safe and dangerous doses of propofol is thin, and according to the drug's guidelines a trained professional must always stay bedside. Home use of propofol is virtually unheard of – safe administration requires both a specially trained anesthesiologist and an array of lifesaving equipment. Murray was trained as a heart doctor, not a pain and sedation specialist.

Murray told investigators he didn't order or buy any propofol, but investigators served a search warrant Aug. 11 at a Las Vegas pharmacy and uncovered evidence showing Murray legally purchased from the store the propofol he gave Jackson on the day he died.

Jackson's family released a statement Monday, saying it has "full confidence" in the legal process and the efforts of investigators. It concludes: "The family looks forward to the day that justice can be served."

Contributing to this report were AP Medical Writer Marilynn Marchione in Milwaukee and Associated Press Writers Alicia Chang in Los Angeles and Michael Gracyzk in Houston.