LOS ANGELES - THE discovery of a potent anesthetic at Michael Jackson's mansion renewed speculation about the role of drugs in the singer's death as preparations for the star's memorial gathered pace on Saturday.

The discovery has raised the stakes in the Jackson probe, which widened earlier this week as the Los Angeles Police Department enlisted the support of the federal Drug Enforcement Administration.

Propofol is commonly used in hospitals to induce unconsciousness in patients before major surgery. Healthcare experts say it should never be used at home and should only be administered by trained anesthesiologists.

'It can be used in lower dosages for sedation, but it is not a drug to be used in a home environment,' anesthesiologist David Kloth told MSNBC, saying proper administering of the drug use was 'incredibly complex.' 'It requires a continuous monitoring of the blood pressure and the person's oxygenation and possibly an EKG (electrocardiogram) because of the potential cardiac effects,' he added.

Jackson died on June 25 after suffering an apparent cardiac arrest. Los Angeles coroners have said a final cause of death will not be known until exhaustive toxicology tests from his autopsy are completed in 'several weeks.' Jackson's family also hired a private pathologist to carry out a separate autopsy but no results of the findings have been made public.

The aftermath of Jackson's death has seen intense speculation about the role of doctors who treated the star.

Police have questioned Jackson's personal physician Conrad Murray but have stressed he is not suspected of criminal wrongdoing.

Associates of Jackson and his family have repeatedly accused unidentified medical professionals of acting as 'enablers' by making prescription drugs readily available.

Family adviser and activist Reverend Jesse Jackson, who is not related to the musical clan, said Saturday the Jacksons still harbored concerns. -- AFP