Autopsy on the way to determine the cause of Prince's death

An autopsy is underway that could provide answers as to why legendary musician Prince collapsed and died at his home in suburban Minneapolis.

Doctor A. Quinn Strobl of the Midwest Medical Examiner's Office began the autopsy about 9 a.m. A statement from the medical examiner said relevant information about Prince's medical and social history will also be gathered as part of the death investigation.

Carver County Sheriff Jim Olson planned to hold a news conference Friday afternoon to summarise the ongoing investigation into the 57-year-old musician's death.

Olson's office was among the agencies who responded to calls for help Thursday morning at Prince's compound in Chanhassen. His deputies continue their investigation into Prince's death.

In the meantime, a promoter said Prince was slated to perform a surprise set of shows earlier this week in St. Louis but cancelled last week because of health concerns.

Promoter Steve Litman said Friday that he'd been working for weeks to set up two surprise pop-up shows on April 18 at the Fox Theatre in St. Louis. Litman is executive producer for concerts at the theatre.

Litman says tickets were set to go on sale April 15, but that Prince's representatives told him late on April 14 that Prince needed to back out because of concern he might have to cancel the shows due to illness.

Prince had performed two concerts in Atlanta earlier on April 14 to make up for concerts that he cancelled, citing the flu, a week earlier. Litman says he'd been talking to Prince's representatives most of that day.

Prince hosted a dance party two days later at his Paisley Park compound in Minnesota.

Adding to the health concerns, Prince's former percussionist says the music star had a history of hip injuries, and Prince himself talked of having epilepsy as a child.

Sheila E. spoke with ABC's "Good Morning America" on Friday, and said that Prince suffered hip injuries while performing and damaged his body when jumping from risers in his high heels during his "Purple Rain" days. Prince was seen in recent years using a cane.

Prince himself revealed in a 2009 interview with Tavis Smiley that he had seizures when he was young and was "born epileptic," though it's unclear if Prince had seizures as an adult.

Prince's death at age 57 has sparked an outpouring of grief from fans, with hundreds gathering outside his studio and in downtown Minneapolis and many more posting remembrances on social networks.

Buildings around the country were lit up Thursday night in his signature purple.