Prince was an alleged cocaine user who could not control his drug habit, according to newly released police call records.
A woman contacted Carver County Sheriff's Office in Minnesota in June 2011 to report that she was "concerned about Prince's cocaine habit".
The caller, whose name has not been released, claimed Prince had "advised her last year in Germany that he cannot control his habit and she was advised to report it".
Police told the woman that because the information was a year old and "she did not specify Prince is in immediate danger" the incident was closed, the documents show.
The records were released by the sheriff's office two weeks after the 57-year-old music superstar was found dead at his Paisley Park estate near Minneapolis.
They also show a caller in January 2015 asked for a message to be delivered to Prince "regarding a mutual son who was having open heart surgery".
The sheriff's office said at the time it would not conduct "any kind of third party messaging" between her and Prince.
On April 21 this year - the day Prince died - a woman called police and claimed she had a child with the musician, a 17-year-old boy, and she wanted her son to attend the funeral.
The sheriff's office left a message for Paisley Park staff, according to the records. Investigators are looking into whether Prince died from an overdose and if a doctor was prescribing him drugs in the weeks before his death.
They are also trying to establish whether a doctor was on the singer's plane when it made an emergency landing less than a week before he died.
The Purple Rain star was found unconscious on the plane after it stopped in Moline, western Illinois, on April 15. He was given a drug used to treat suspected overdoses.
Prescription drugs were found at Prince's home following his death. Results of a post-mortem examination are not expected for several weeks.
Prince's long-time friend and collaborator Sheila E said he had hip and knee problems that were the result of years of jumping off speakers in heels while performing on stage.