LOS ANGELES - Michael Jackson's death was a homicide caused primarily by the powerful anesthetic propofol and another sedative, the Los Angeles County coroner said yesterday in a highly anticipated ruling increasing the likelihood of criminal charges against the pop star's doctor.

The coroner did not release Jackson's full autopsy report, citing a security hold requested by Los Angeles authorities investigating the case, and declined to comment beyond a short statement citing the manner and cause of death.

The determination of a homicide confirmed what the Associated Press first reported Monday.

Separately yesterday, California Attorney General Jerry Brown said he was opening an independent investigation of several doctors whose names have come up in the probe of Jackson's death. Brown's statement did not identify the doctors.

The coroner's office determined that Jackson died of "acute propofol intoxication." Lorazepam, a sedative sold under the brand name Ativan, contributed to his death. Other drugs detected in Jackson's body were the sedatives midazolam and diazepam, the painkiller lidocaine, and the stimulant ephedrine.

Jackson, 50, died June 25. Conrad Murray, a cardiologist who was the star's personal physician, told police he gave Jackson propofol that morning after a series of sedatives failed to help Jackson sleep.

Murray is the target of what police call a manslaughter inquiry. Warrants served at his home and businesses in Las Vegas and Houston sought evidence detailing how he procured propofol. Jackson's interactions with at least six other doctors are being scrutinized.

Except for a brief video posted to YouTube earlier this month, Murray has not spoken publicly since Jackson's death. In the video, he said: "I told the truth and I have faith the truth will prevail."

Murray's attorney, Edward Chernoff, said he was disappointed the full autopsy report was not released. Without that, it was impossible to seek independent expert opinion on the significance of the various drugs detected, he said.

"Release the toxicology report, the whole thing. Sunlight is the best disinfectant," Chernoff said. "This smells like gamesmanship."

The coroner said the security hold would remain until the investigation is wrapped up. The Los Angeles Police Department and the District Attorney's Office said they did not know when that would be.

In the last seven years, just a handful of doctors have been convicted of manslaughter, mostly involving patients' use of painkillers. To win a conviction, prosecutors would have to show that Murray acted recklessly and with negligence.