Los Angeles  - The release of the results of Michael Jackson's autopsy have been delayed indefinitely as investigators continue to probe the singer's drug habit and the doctors that enabled it, the Los Angeles Times reported Friday.

The decision by the Los Angeles County coroner's office came after it had already postponed the release of the results once from this week to next week.

The delay comes as investigators are trying to piece together communications between Jackson's personal physician Dr Conrad Murray and other medical practitioners involved in treating Jackson.

Police have searched the home and business premises of Murray in Las Vegas and Houston. The search warrants indicated that Murray is under investigation for prescribing excessive narcotics to an "addict" - actions that could lead to a manslaughter charge against the physician, ABC News reported.

Jackson died of cardiac arrest on June 25, just as he was about to embark on a 50 date comeback tour in London. Police sources believe that Jackson used the hospital anesthetic propofol as a sleeping aid, and that Murray administered the dose that caused his cardiac arrest.(dpa)