Soon after Prince was found dead in his Minnesota home in April of this year, rumors swarmed that he too had succumbed to a drug overdose like fellow music icon Michael Jackson. In June, reports confirmed that the extremely potent opioid fentanyl was the substance that caused the pop legend's death. Fentanyl is 100 times more potent than morphine and 50 times more powerful than heroin, but on August 21, an anonymous official source involved with the investigation told the Associated Press that it might not have been prescription fentanyl that killed the musician. It was revealed that counterfeit pills containing bootleg fentanyl had been found on his estate.
The AP source said that nearly two dozen pills found in one Aleve bottle were falsely labeled as "Watson 385." According to Drugs.com, that stamp is used to identify pills containing a mix of acetaminophen and hydrocodone, but the official said these particular pills that were found actually contained fentanyl, lidocaine, and U-47700 — a synthetic drug that is eight times more powerful than morphine. Among the other dozens of pills seized from Paisley Park, they were found to have other drugs in them, including oxycodone, codeine, and some were not controlled substances, but were aspirin, and Vitamin C.
Though fentanyl is known as a prescription drug that is most commonly available as a patch placed on the skin, in recent years, a bootleg version of the drug believed to derive from China has flooded the black market in both the US and Canada. Fentanyl is increasingly playing a role in the thousands of overdose deaths in the United States.  More than 700 people died due to overdoses from the potent opioid between 2013 and 2015. This number is likely higher than reported because fentanyl isn't always tested for.
Source: vice.com