Michael Jackson Homicide Investigation

LOS ANGELES - The Los Angeles County coroner has ruled Michael Jackson's death a homicide and a combination of drugs was the cause, a law enforcement official told The Associated Press, a finding that makes it more likely criminal charges will be filed against the doctor who was with the pop star when he died.

Forensic tests found the powerful anesthetic propofol acted together with at least two sedatives to cause Jackson's death June 25 in his rented Los Angeles mansion, according to the official, who spoke on condition of anonymity because the findings have not been publicly released.

Dr. Conrad Murray, a Las Vegas cardiologist who became Jackson's personal physician weeks before his death, is the target of a manslaughter investigation by the Los Angeles Police Department. A search warrant affidavit unsealed Monday in Houston includes a detailed account of what Murray told investigators.

According to the document, Murray said he'd been treating Jackson for insomnia for about six weeks with 50 mg of propofol every night via an intravenous drip. But he said he feared Jackson was forming an addiction to the anesthetic, which is normally used in hospitals only, and was attempting to wean his patient by lowering the dose to 25 mg and adding the sedatives lorazepam and midazolam.

That combination succeeded in helping Jackson sleep two days prior to his death, so the next day, Murray told detectives he cut off the propofol -- and Jackson fell asleep with just the two sedatives.

Then around 1:30 a.m. on June 25, starting with a 10-milligram tab of Valium, Murray said he tried a series of drugs instead of propofol to make Jackson sleep. The injections included two milligrams of lorazepam around 2 a.m., two milligrams of midazolam around 3 a.m., and repeats of each at 5 a.m. and 7:30 a.m. respectively.

But they didn't work.

Murray told detectives that around 10:40 a.m. he gave in to Jackson's "repeated demands/requests" for propofol, which the singer referred to as his "milk." He 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. No more than two minutes later, he returned -- and found Jackson had stopped breathing.

"There's no surprise there" that death could result from such a combination, 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 all the other sedatives "tipped the balance."

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.

When he died, Jackson was skinny but not overly emaciated, and his body had bed sores, the official said. The singer is believed to have developed bed sores in the months following his 2005 acquittal of child molestation charges, when he went into seclusion and spent long stretches in bed.

Murray has spoken to police and last week released a video saying he "told the truth and I have faith the truth will prevail." Murray did not say anything about the drugs he gave to Jackson. Murray's attorney, Edward Chernoff, had no immediate comment but has previously said Murray never administered anything that "should have" killed Jackson.

A call to the coroner's office was not returned Monday.

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."

The 25 milligrams of propofol Murray told police he gave Jackson the day he died "is not a whopping amount," said Lee Cantrell, director of the San Diego division of the California Poison Control System. But by combining propofol with a cocktail of the other sedatives, known as benzodiazepines, it "may have been the trigger that pushed him over the edge," Cantrell said.

Cantrell said it's perplexing that someone would give various benzodiazepines if one was found not to be effective.

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

The affidavit says Murray told investigators he didn't order or buy any propofol and had found about eight bottles of it in Jackson's home along with numerous other medications. 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 the day he died.

Murray didn't tell paramedics or doctors at UCLA hospital where Jackson was rushed June 25 about any drugs he administered other than lorazepam and flumazenil, according to the affidavit. The document says 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 coroner's office has not publicly released its autopsy findings, citing a request from police detectives to withhold results until their investigation is complete.

Homicide, or "death at the hands of another," is one of several possible findings in a coroner's death investigation. The designation does not necessarily mean a crime was committed though it is a useful starting point for prosecutors, said Dr. Michael Baden, the former chief medical examiner in New York City and a forensics expert involved in many high-profile murder cases.

"It is an easier prosecution when the medical examiner calls it a homicide," said Baden, who is not involved in the Jackson investigation.

Associated Press writers Justin Pritchard and Alicia Chang in Los Angeles and Michael Gracyzk in Houston contributed to this report.