An autopsy on U.S. music superstar Prince on Friday sought to determine why the innovative performer died, but authorities cautioned it could take weeks before the results are made public.
The intensely private musician, whose hits included "Purple Rain" and "When Doves Cry," was found dead at his home in suburban Minneapolis on Thursday at the age of 57, shocking millions of fans around the world and prompting glowing tributes by fellow musicians.
The local Carver County Sheriff's Office is investigating the circumstances of his death, and Sheriff Jim Olson was due to hold a news conference at 3 p.m. (4 p.m. ET, 2000 GMT).
Olson's spokesman cautioned, however, that the investigation was ongoing and that the sheriff may be unable to answer the most pressing questions.
The influential star, born Prince Rogers Nelson, was found unresponsive in an elevator at the Paisley Park Studios complex where he lived in the suburb of Chanhassen, authorities said.
The local medical examiner's office conducted a post-mortem examination on Friday morning for four hours, but said its results could be some time coming.
The body will be released to the family later on Friday, the Midwest Medical Examiner's Office added in a statement.
"As part of a complete exam, relevant information regarding Mr. Nelson's medical and social history will be gathered. Anything which could be relevant to the investigation will be taken into consideration," the statement said.
No information will be released until all results have been obtained, it added. "Gathering the results will take several days and the results of a full toxicology scan could likely take weeks," the medical examiner's office said.
Prince's music blended styles including rock, jazz, funk, disco and R&B, and it won him seven Grammy Awards as well as an Oscar. He had been on a U.S. tour as recently as last week.
But he was briefly hospitalized a week ago after his plane made an emergency landing in Moline, Illinois, suffering from what his representative told celebrity news website TMZ was flu.
Nevertheless, the star hosted a party at Paisley Park last Saturday night at which one attendee said Prince played two tunes on a piano and then introduced fans to his doctor.
Prince first found fame in the late 1970s before becoming one of the most inventive forces in American pop music.
On a trip to London, U.S. President Barack Obama said he listened to "Purple Rain" and "Delirious" on Friday morning at the U.S. ambassador's residence to get "warmed up" for his meetings.
"I loved Prince ... It's a remarkable loss," Obama told a news conference.
As well as singing and songwriting, Prince played multiple instruments including guitar, keyboards and drums. A Jehovah's Witness and a strict vegan, he sold more than 100 million records and was inducted into the Rock and Roll Hall of Fame in 2004.
Record producer L.A. Reid told NBC's "Today" show on Friday that he was perplexed by the death of his friend.
"The Prince I know was super-healthy, vegan, wasn't an abuser of drugs, wasn't an abuser of alcohol," Reid said. "He was clean and he looked young and he looked really healthy and vibrant, so the whole thing is really mysterious to me."
During his life, Prince was known as fiercely determined to protect his intellectual property.
How others might profit from his legacy hinges on how astute he was about arranging for control of his music after death. Twice divorced with no surviving children, he apparently lacked any immediately identifiable heirs.
Ex-wife Manuela Testolini said that as well as being a husband and friend, Prince had been a "fierce philanthropist" who encouraged her to set up her own charity. She had contacted him only a few days ago, she added, to tell him she was building a school in his honor.
"I am heartbroken beyond words," Testolini said in a statement on Friday.
(Additional reporting by Jane Ross in Minneapolis, Alex Dobuzinskis, Dan Whitcomb and Steve Gorman in Los Angeles, and Suzannah Gonzales in Chicago; Writing by Daniel Wallis; Editing by Frances Kerry and Cynthia Osterman)