Several months ago, Prince’s official autopsy confirmed that the singer died of an overdose of the opioid painkiller fentanyl. Now, details from the investigation of his death reveal the pills may have come from a counterfeit drug distributor and that no doctor’s prescription was likely involved in the 57-year-old star’s tragic death, Vanity Fair reports.

According to several recent news stories, pills testing positive for fentanyl were discovered at Prince’s Paisley Park home inside an Aleve bottle shortly after his death. The medication was falsely labeled as “Watson 385.” According to, Watson 385 is typically a blend of acetaminophen and hydrocodone (similar to the brand-name prescription drug Vicodin) commonly sold online by counterfeit drug companies.

Addiction experts say these counterfeit pills can be extremely dangerous because they sometimes contain fentanyl instead, a drug that’s 50 times more powerful than heroin. For this reason, Watson 385 users don’t always know what they’re taking or what precautions to observe, which may have been a mistake Prince made during his final hours.

Prince’s official death investigation also reveals that the star—who was battling chronic pain—had stashes of Watson 385 distributed around his dressing room at home and in suitcases he carried when traveling. But only one bottle of the pills tested positive for fentanyl. According to health officials connected to the case, Prince had no prescription for any controlled substances in his home state during the past year. In addition, the entertainer didn’t test positive for fentanyl when he overdosed on Percocet a week before his death.

This means that it’s unlikely Prince’s use of fentanyl was long-term, and the fatal dose of the drug may possibly have been consumed 24 hours before he died. It’s also likely that Prince or his doctors didn’t know exactly what he was taking when he swallowed the pills that ended his life.

To learn more about the dangers of counterfeit drugs, click here.