Doctors conducted an autopsy on the body of Michael Jackson on Friday but could not immediately determine what killed the "King of Pop," amid reports he had been injected with a narcotic painkiller shortly before collapsing.
Jackson was in full cardiac arrest when paramedics arrived at his rented mansion in the Holmby Hills neighborhood of Los Angeles on Thursday afternoon, with his personal physician trying desperately to revive him.
The 50-year-old pop superstar was rushed to nearby UCLA Medical Center, where he was pronounced dead without regaining consciousness.
"The cause of death (determination) 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."
Speaking to a throng of reporters outside the coroner's office, Harvey said, "There was no indication of any external trauma or indication of foul play to the body of Mr. Jackson."
Police said they were seeking to question Jackson's personal physician, identified by news media as Houston-based cardiologist Dr. Conrad Murray.
Jackson's body will be released to family members after they choose a mortuary for funeral arrangements, Harvey said. There was no immediate word on when he would be laid to rest.
Celebrity website TMZ.com, citing an interview with an unidentified "close member" of the Jackson family, reported the entertainer was injected with Demerol about half an hour before he went into cardiac arrest.