A toxicology report obtained by the Associated Press on Monday reveals that Prince had an “exceedingly high” concentration of fentanyl in his body when he died. Fentanyl is a synthetic opioid that’s 50 times more powerful than heroin. According to the report, the concentration of fentanyl in Prince’s blood was 67.8 micrograms per liter. Fatalities have been documented in people with blood levels ranging from 3 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,” notes Dr. Lewis Nelson, chairman of emergency medicine at Rutgers New Jersey Medical School. Prince was found alone and unresponsive in an elevator at his Paisley Park estate on April 21, 2016. He was 57 at the time of his death.