Police seized vials of prescription drugs from the entertainer's rented Holmby Hills estate in Los Angeles as part of their ongoing investigation into the cause of the King of Pop's fatal cardiac arrest on June 25, leading to speculation that Jackson suffered a drug overdose.
A preliminary report from the coroner's office -- indicating no evidence of foul play had been found -- stated that medical examiners would need four to six weeks to complete toxicology, neuropathology and pulmonary tests before determining Jackson's exact cause of death.
According to Los Angeles' Assistant Chief Coroner Ed Winter, some results from toxicology tests are in and the rest should be ready later this week or early next week.
However, the coroners are holding back on fuelling speculation over exactly what killed Jackson until they have the complete picture of results.
Winter claims the office is "still on track" and will announce when all test results have been returned, before releasing them into the public domain the following day.
Earlier this month, a senior Los Angeles police chief confirmed that cops are refusing to rule out the possibility Jackson was murdered.
The head of L.A. police, William Bratton, told CNN, "Are we dealing with a homicide or are we dealing with accidental overdose? I don't have that information... We are still awaiting corroboration from the coroner's office as to cause of death."
Members of Jackson's family have also raised suspicion over how the star died, with father Joe and sister La Toya insisting foul play was involved.
La Toya told British newspaper the News of the World on Sunday, "I believe Michael was murdered, I felt that from the start. Not just one person was involved; rather it was a conspiracy of people. He was surrounded by a bad circle... Less than a month ago, I said I thought Michael was going to die before the London shows because he was surrounded by people who didn't have his best interests at heart... I said to my family a month ago, 'He's never going to make it to London.' He was worth more dead than alive."
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