WASHINGTON — (CNN) Toxicology tests for Prince concluded that the entertainer died from an accidental overdose of the opioid fentanyl, according to a report on his death by the Midwest Medical Examiner’s Office.

Music legend Prince died of an opioid overdose, the Minneapolis Star Tribune reported Thursday, citing a source familiar with the investigation into the singer’s death.

Prince, whose full name was Prince Rogers Nelson, died April 21 at the age of 57.

He was found unresponsive in an elevator at Paisley Park, his home and recording studio in Chanhassen, Minnesota.

Paramedics performed CPR but were unable to revive him, authorities said.

An autopsy was conducted the day after his death but official results have not been released.

Since then, information has emerged about the entertainer’s alleged abuse of prescription drugs.

An attorney for Prince’s half-siblings said they revealed the singer had an addiction to Percocet decades before he died.

Federal prosecutors and the Drug Enforcement Administration are investigating how Prince obtained prescription medications and from whom, the agencies said.

The day before Prince died, his team called an eminent opioid addiction specialist in California seeking urgent help for the singer, an attorney working for the specialist and his son said.