A toxicology report from Prince’s autopsy, obtained by Associated Press, shows the iconic musician had what several experts deemed an “exceedingly high” concentration of fentanyl in his body when he died.

Prince was 57 when he was found alone and unresponsive in an elevator at his Paisley Park estate on 21 April, 2016. Public data released six weeks after his death showed he died of an accidental overdose of fentanyl, a synthetic opioid 50 times more powerful than heroin.

A confidential toxicology report provides some insight into just how much fentanyl was in his system. Experts who are not connected to the Prince investigation said the numbers leave no doubt that fentanyl killed him.

According to the AP, the confidential toxicology report indicates that "concentration of fentanyl in Prince's blood was 67.8 micrograms per liter." As the wire service notes, "fatalities have been documented in people with blood levels ranging from three to 58 micrograms per liter."

"The amount in his blood is exceedingly high, even for somebody who is a chronic pain patient on fentanyl patches," Dr. Lewis Nelson, chairman of emergency medicine at Rutgers New Jersey Medical School, told the wire service. He called the fentanyl concentrations “a pretty clear smoking gun”.