Jerry Brown, California's attorney general filed a petition in Los Angeles Superior Court on behalf of the California Medical Board asking that a judge restrict the medical license of Doctor Conrad Murray, who faces involuntary manslaughter charges, as a condition of his bail.

Murray was attending to Jackson, 50, before his sudden death last June 25 and police say he has admitted to investigators that he gave the singer the drug propofol to help him sleep. The powerful anesthetic is typically used on patients undergoing surgery.

(The) Defendant is alleged to have administered a lethal dose of propofol and other powerful drugs to patient M.J., which resulted in the patient's death, Brown said in the 12-page court filing.

The exercise of such poor professional judgment and placing the life of a patient in jeopardy requires that the (California Medical) Board take measures to protect the public from future harm.

Murray, a cardiologist who was hired last May to care for Jackson as the entertainer prepared for a series of comeback concerts, has pleaded not guilty. He is free on $75,000 bail and faces four years in prison if convicted.

Murray has been the focus of a police probe since the Los Angeles coroner's office ruled Jackson's death was a homicide, caused by propofol and the sedative lorazepam.

Toxicology tests following an autopsy also found painkillers, sedatives and a stimulant in Jackson's body.

Murray and his legal defense team have insisted he did nothing wrong and Murray told police he was not the first doctor to give Jackson propofol to help him sleep.

Last month, a judge rejected a request by Los Angeles prosecutors to suspend Murray's license but ordered him not to use anesthesia on his patients.

Brown, a former California governor who announced on March 2 he would seek the Democratic nomination for the governorship, has waged a campaign against doctors who over-prescribe drugs.