A toxicology report says musician Prince had an "exceedingly high" amount of fentanyl in his body when he died in 2016. Six weeks after he died, the Midwest Medical Examiner's Office said he died of an accidental fentanyl overdose.

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The Associated Press reported that it obtained a confidential toxicology report that said Prince had a concentration of 67.8 micrograms of fentanyl per liter in his blood. The report said people who have died from a fentanyl overdose had blood levels from 3 to 58 micrograms per liter.

Related: Prince died of fentanyl overdose, autopsy report released

"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 AP.

The concentration of fentanyl was “a pretty clear smoking gun,” Nelson said.

People reported that unsealed court documents released in April 2017 showed investigators found multiple prescription drugs hidden in Prince's Paisley Park estate in Minneapolis. The documents also said opioids were found in the house in containers other than pill bottles.

Prince died at age 57 in his home on April 21, 2016.