The "Purple Rain" hitmaker tragically passed away in 2016 from an accidental fentanyl overdose at the age of 57, leaving behind a vast collection of unreleased music which was known only as "the vault".
A toxicology report from Prince's autopsy showed last month that the singer had "exceedingly high" concentrations of the opioid painkiller fentanyl in his body.
Metz said law enforcement was unable to determine who'd provided the counterfeit Vicodin laced with fentanyl that killed Prince despite "intensive investigation".
Metz says there may be speculation on how Prince got the pills, but he can not say conclusively that any individual enabled that.
Dr Schulenberg admitted no liability as part of the settlement and has maintained he did not prescribe drugs to anyone with the intention they be redirected to Prince.
The messages show Johnson contacted Schulenberg on April 7, 2016 because Prince wasn't feeling well and wanted fluids.
Prince Death Investigation: No Charges to Be Filed, Minnesota Prosecutor Rules
And Metz says he doesn't think the people around Prince knew it either. News broke shortly after that the icon had died from an opioid overdose. Prince had been experiencing back pain from years of performances, Johnson said.
Wright, who didn't remember how many pills Prince claimed he took, told investigators that the amount shouldn't have been enough to require the administration of Narcan.
"There is no evidence the pills that killed Prince were prescribed by a doctor".
State prosecutors say they haven't determined the source of the fentanyl and no charges will be filed.
However, Dr Michael Schulenberg, the doctor who had treated the superstar just before his death, has agreed to pay US$30,000 (S$39,000) to settle a federal civil violation for an illegal prescription. The official cause of death was ruled to be a self-administered overdose.More news: Apple offers free battery replacement to select 13-inch MacBook Pro users