A 911 caller from Michael Jackson's home says he wasn't breathing or responding to efforts to revive him.
The Los Angeles Fire Department released the 911 call Friday.
The caller reported that Jackson was on a bed, he wasn't breathing and wasn't responding to CPR.
The unidentified caller said Jackson only was with his personal doctor at the time.
Jackson was pronounced dead later Thursday at UCLA Medical Center.
Los Angeles County coroner's Lt. Brian Elias says an autopsy began shortly after 9 a.m. Friday and could take three to four hours.
Additional laboratory tests, including toxicology tests, are likely and those results wouldn't be known for several weeks.
Michael Jackson's body is now at the Los Angeles County coroner's office and an autopsy is scheduled.
Jackson's brother Jermaine said earlier at a hospital press conference that it's believed that the pop star died of cardiac arrest.
Jermaine Jackson cautioned that the cause of his death would not be known until the autopsy was performed.
He said Michael Jackson's personal doctor and paramedics tried to resuscitate him at his rented home in Holmby Hills. A team of doctors at UCLA Medical Center also tried for more than an hour.
Los Angeles police Lt. Gregg Strenk said at a separate news conference that police robbery-homicide detectives have been ordered to investigate, which is common in a high-profile case.
Michael Jackson was rushed to the hospital this afternoon. Multiple reports now say the singer, age 50, has died.
Officials say he was not breathing when paramedics arrived at his Los Angeles home, and CPR was performed in the ambulance.
A fire department official tells the Los Angeles Times that Michael Jackson has been rushed to the hospital.
Steve Ruda told the newspaper Thursday that Jackson was not breathing when Los Angeles Fire Department paramedics responded to a call at his Los Angeles home about 12:30 p.m.
The paramedics performed CPR and took him to UCLA Medical Center, Ruda told the paper.
L. Londell McMillan, a lawyer for Jackson, did not have any information. Messages left for other Jackson associates were not immediately returned.
The hospitalization and death was first reported by the Web site TMZ.