An autopsy was conducted Friday at the Midwest Medical Examiner's Office in Ramsey, Minnesota, but it could be days or weeks before results are complete, spokeswoman Martha Weaver said. The autopsy began at 9 a.m. CT (10 a.m. ET) and lasted four hours, she added.
Carver County Sheriff Jim Olson said there were no obvious signs of trauma on Prince's body when he was found. There is no reason to believe Prince's death was a suicide, Olson said.
The medical examiner's office said it "will not release information until the exam is complete and all results are obtained."
Prince, whose full name was Prince Rogers Nelson
, died Thursday at age 57. He was found unresponsive in an elevator at Paisley Park, his home and recording studio, in Chanhassen, Minnesota.
Paramedics tried to perform CPR but were unable to revive him, authorities said. He was pronounced dead at 10:07 a.m., less than 30 minutes after sheriff's deputies responded to a medical call at the scene.
Prince's body was released to his family Friday, Weaver said.
Found alone at Paisley Park
The last time Prince was seen alive was at 8 p.m. Wednesday when he was dropped off at Paisley Park, the sheriff said. He was alone in the complex when he was found, which Olson said was not unusual given that Prince was a private person.
When members of his staff were unable to contact him Thursday morning, they went to Paisley Park to check on him and discovered him slumped in the elevator, Olson said.
It's unclear how long Prince had been there, he said, and he wouldn't say whether there were surveillance cameras in the building.
"Because this was an unwitnessed death of a middle-aged adult, the decision was made to process the scene," Olson said. "That is also normal protocol. It is not different from what we normally would do."
The sheriff would not say whether investigators removed any items from the building. And he said he could not confirm whether Prince was taking any medication at the time of his death.
But, he promised, "We are going to leave no stone unturned with this and make sure the public knows what happened."
Tributes, dancing and pizza
For a second day, fans gathered at Paisley Park to leave tributes of flowers, balloons and signs. Some were dressed in Prince's signature color, purple.
Amid bouquets of flowers stuck into the chain-link fence, a man in a purple hoodie used a black ribbon to tie on a single rose.
Prince's staff and family delivered pizza to the fans Friday evening.
"We just wanted to thank you for your support," one of them said as she handed out pizza boxes.
Balloons and flowers also piled up at First Avenue, the downtown Minneapolis nightclub that became a landmark after Prince used it in the 1984 movie "Purple Rain."
One fan left a purple and blue paisley scarf amid the candles and homemade signs.
The cast of the Broadway musical "The Color Purple" paid an emotional tribute to Prince at the end of their performance Thursday night. Stars Jennifer Hudson and Cynthia Erivo belted out "Purple Rain" while everyone in the theater waved their arms and sang the refrain.
Around the corner it was an onstage Prince party at the Broadway musical "Hamilton," with costumed cast members dancing wildly to his 1984 hit, "Let's Go Crazy" as the audience clapped along.
'A remarkable loss'
In London, President Barack Obama praised the music legend and said he and his staff listened to "Purple Rain" ahead of a meeting with the British Prime Minister on Friday.
"He came to perform at the White House and was extraordinary, and creative, and original, and full of energy. So it's a remarkable loss," Obama said.
Prince became a Jehovah's Witness in 2003, and the denomination released a statement saying it is saddened by his death.
"Prince found fulfillment as a Witness and in sharing his faith with others," the statement read.
"Our thoughts are with his family and friends, particularly his fellow worshipers at the Saint Louis Park congregation of Jehovah's Witnesses in Minnesota. We hope that all find comfort in the Bible's promise of a future time when death, pain and tears will be no more."
'Purple Rain' movie returns
AMC Theatres said Friday that the movie "Purple Rain" will return for a limited theatrical run.
The cult classic starring Prince and Apollonia Kotero will run from April 23-28. AMC said it will play at 87 of its theaters across the country.
The movie earned Prince an Academy Award for best original song.