Prescription drugs were found in Prince's possession when he died, according to US reports.
Officials told NBC News the painkillers were discovered in his Minneapolis home - but it is as yet unclear if they played any part in his death.
The pop star died aged 57 on April 21 after being found collapsed in a lift at his Paisley Park estate.
A Prince fan captured the music legend's last performance of one of his most famous hits, Purple Rain, at his final concert in Atlanta last week.
The pop star died unexpectedly at his home in Minneapolis today at the age of 57.
Jake Reuse said he will cherish the videos and is "beyond thankful" that he got to see the star's last show.
The painkillers were reportedly found in the singer's possession when he died - but it is unclear if they played any part in his death.
Mourners celebrate pop icon at private memorial at Paisley Park estate.
Star's ex-manager voiced concerns over whether whoever inherits the star's fortune, and valuable catalogue of works, will know what to do.