Prince was 57 when he was discovered alone and unresponsive in an elevator at Paisley Park on April 21.
Approximately a year after Prince's accidental overdose death at his suburban Minneapolis studio and estate, investigators are yet to find out how he acquired the fentanyl that killed him.
However, the newly unsealed documents provide the clearest picture yet of the Purple Rain hitmaker's struggle with opioid painkillers.
Investigators talked to plenty of people at Paisley Park where the star's body was discovered.
The people told the investigators that Prince had been "going through withdrawals, which are believed to be the result of the abuse of prescription medication."
When police later checked a database used to monitor who is getting prescriptions for controlled substances, they found no record of Prince.
There was, however, a prescription for the opioid painkiller oxycodone. The prescription was written for Kirk Johnson, Prince's bodyguard.
The opioid prescription was dated April 14, 2016, the same day Prince was revived with an anti-overdose drug after getting sick on a plane.
Dr. Michael Schulenberg, who wrote the prescription, told the police he put the prescription in the bodyguard's name to protect Prince's privacy.
In a statement, Schulenberg's lawyer, Amy Conners, said that her client never prescribed opioids to Prince directly, or to another party with the intent of providing them to the award-winning musician.
Writing a prescription under another person's name is contrary to state and federal law.