The "Purple Rain" singer is said to have administered the drug himself.
The Midwest Medical Examiner’s Office has confirmed that Prince died of an opioid overdose.
Read: Prince Had Been Dead For Hours When He Was Found in His Home's Elevator: Report
The Examiner released the report Thursday afternoon, saying test results showed he passed due to an overdose of fentanyl, a powerful opioid painkiller.
Prince Rogers Nelson investigation results attached pic.twitter.com/CMt6lQSGxJ
— Midwest Medical Exam (@MidwestMedExam) June 2, 2016
Prince, whose real name was Prince Rodgers Nelson, was found unconscious April 21 in an elevator inside his Paisley Park Compound in Minnesota.
According to the one-page report, Prince administered the drug himself, but it's not known when he took the fatal amount.
The Examiner’s office also stated that they had completed its death investigation.
Read: Justin Timberlake, Katy Perry Lead Tributes to Prince: 'The World Lost A Lot of Magic'
The 57-year-old icon died less than a week after his plane made an emergency stop in Illinois from Atlanta for medical treatment. Reports indicate that the singer was found unconscious on the plane and first responders gave him a shot of Narcan, a drug used in suspected opioid overdoses.
According to the Associated Press, more than 700 fentanyl-related overdoes were reported by the Drug Enforcement Administration between 2013 and 2014.
Watch: Dr. Conrad Murray Thinks Prince's Doctors Need a Good Attorney
