The cause of Michael Jackson's death will not be known for up to six weeks after the medical examiner has ordered for additional testing to determine the possible involvement of drugs in the stars’ death.

Jackson collapsed in his rented mansion in Holmby Hills and was in full cardiac arrest when paramedics arrived.

After an autopsy lasting several hours, Los Angeles County coroner's spokesman Craig Harvey told reporters on Friday that examiners had found no evidence of external trauma or foul play on Jackson's body.

The cause of death has been deferred, which means that the medical examiner has ordered additional testing such as toxicology and other studies, Los Angeles County Coroner's spokesman Craig Harvey said. Those tests we anticipate will take an additional four to six weeks.

Police said they were seeking to question Jackson's personal physician, identified by news media as Houston-based cardiologist Dr. Conrad Murray.

According to reports from TMZ website, Jackson was injected with Demoral approximately thirty minutes before he went into cardiac arrest.

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