As Michael Jackson fans continued to mourn the late King of Pop, police on Saturday were tracking how, and from who, the super star got prescription drugs that allegedly caused his unexpected death.

Investigators of the Los Angeles Police Department were looking into the activities of at least five doctors who prescribed drugs to Jackson, who died last week at a Los Angeles hospital soon after being rushed there in a cardiac arrest.

No information has been released from two autopsies conducted on Jackson's body, but speculation continues to focus on the possibility of a drug overdose, and specifically on the anesthetic propofol, which investigators reportedly found at Jackson's home.

Propofol, marketed under the brand name Diprivan, is a strong anesthetic used in surgical and clinical settings.

Demerol and OxyContin, also known "hillbilly heroin," are among the other painkillers that Jackson was allegedly using.

LAPD detectives last weekend questioned Jackson's personal doctor Conrad Murray, who was at the home when Jackson stopped breathing. Murray's lawyer said the doctor had nothing to do with Jackson's death and will fully cooperate with investigators.

The LAPD confirmed that Murray was cooperating.

However, medical experts pointed out that Murray is an anesthesiologist who could have had access to propofol.

It was highly unusual for a personal doctor to be an anesthesiologist rather than a general practitioner or some other specialty, experts said.

Local media reported that Jackson made the rounds at various doctors' offices in Los Angeles, often getting anesthesia for minor outpatient procedures that do not normally require painkillers.

The U.S. Drug Enforcement Administration (DEA) and California state Attorney General's Office last week confirmed that they were asked to join the investigation into Jackson's death.

California law enforcement investigators are using a computer database to mine for information on prescription drugs to be passed on to LAPD investigators. The database contains the name of doctors who have prescribed controlled substances, the names on prescriptions, the quantity and date.

The DEA is expected to look into whether doctors who prescribed painkillers to Jackson actually saw the singer before giving him drugs, as required by law, according to the Los Angeles Times.

It is still unclear whether prescription drugs contributed to Jackson's death, as the Los Angeles County coroner's office, which conducted an autopsy, deferred a decision on the cause of death pending toxicology tests.

Meanwhile, a private pathologist also failed to provide any clue on the pop icon's death one week after he was hired by the Jackson family to conduct an independent autopsy.

It is expected that a doctor could face manslaughter charges if autopsy results prove Jackson died from a painkiller and investigators trace the drug to the doctor who gave the prescription.

Source: Xinhua