According to officials close to the investigation, pills at Prince's estate contained fentanyl, reports The Associated Press, according to Billboard. Fentanyl is a synthetic opioid 50 times more powerful than heroin.

The official, who spoke to the AP on the condition of anonymity because the investigation is ongoing, said that some of the pills were falsely labeled "Watson 385"—a stamp that is used to identify pills containing a mix of acetaminophen and hydrocodone. The official said about a dozen tablets were found in a dressing room at Paisley Park, but the vast majority was in bottles of Vitamin C and aspirin that had been tucked inside a suitcase and bags -- including one Prince often carried with him.

According to the AP, authorities are still investigating how Prince obtained the drugs. However, tests on Prince prior to his death did not show fentanyl in his system.  The official indicated that means the musician wasn't a long-time abuser of that drug, but probably took a fatal dose sometime in the 24 hours before he died.

The official said that the autopsy report also shows Prince had diazepam (an anti-anxiety pill sold as Valium which can also be used to control seizures, which Prince suffered from as a child) in his system, along with lidocaine and hydrocodone acids. Lidocaine is a local anesthetic.

This latest information comes on the heels of an announcement that Prince's Paisley Park estate will be turned into a museum. CORE Media Group, the entertainment company behind the Graceland estate of the late Elvis Presley, is reportedly developing a Prince museum with assistance from Berner Trust, the administrators of Prince’s estate.

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