Several pills taken from Prince’s estate in Paisley Park after his death were counterfeit drugs that actually contained the powerful opioid fentanyl, an official close to the investigation has revealed.

Many of the pills were found inside aspirin and vitamin bottles tucked in a suitcase, in duffel bags and in a dressing room, the source told the Associated Press.

Prince performing on stage at the Brit Awards
(Yui Mok/PA)

Autopsy results released in June showed Prince died on April 21 of a fentanyl overdose.

Prince had no prescription for any controlled substances in the state of Minnesota in the 12 months before he died, the official said.

Prince
(Fiona Hanson/PA)

Authorities are still investigating how Prince obtained the drugs.