An autopsy was performed on Friday on Michael Jackson’s body however the exact cause of death still remains a mystery.

Investigators are suspecting the possible involvement drugs in the death of the King of Pop and have called for additional tests after they found no 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.

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

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.

TMZ, citing family members, said Jackson received a daily shot of Demerol, a narcotic painkiller, and that the family believed his death was caused by an overdose of the drug.

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Michael Jackson death still unsolved after autopsy