By Todd Melby
CHASKA, Minn. (Reuters) - A two-year investigation into the death of "Purple Rain" singer Prince failed to determine where he obtained a counterfeit painkiller laced with fentanyl, resulting in no criminal charges, a Minnesota prosecutor said on Thursday.
"Law enforcement was unable to determine the source of the counterfeit vicodin laced with fentanyl," Carver County Attorney Mark Metz told a news conference. "We simply do not have sufficient evidence to charge anyone with a crime related to Prince's death."
Prince, 57, was found dead at his Paisley Park home and recording studio complex near Minneapolis on April 21, 2016. The official cause of death was a self-administered overdose of the painkiller fentanyl, which is 50 times stronger than heroin.
"Nothing in the evidence suggests Prince knowingly ingested fentanyl," Metz said, adding there was "no evidence that the pills that killed Prince were prescribed by a doctor."
"There is no reliable evidence showing how Prince obtained the counterfeit vicodin laced with fentanyl or who else may had a role in delivering the counterfeit vicodin to Prince," Metz said.
Prince, known for his androgynous style and sexually charged songs, crafted a public image of living a clean and healthy vegan lifestyle.
But the investigation, which included searches of Prince's computer, mobile phone records of his friends and interviews with associates, determined that Prince suffered from severe pain for a number of years and numerous painkillers were found in his residence, according to Metz.
Some of the pills were prescribed to his bodyguard Kirk Johnson to protect the singer's privacy, Metz said.
Johnson "continues to deny that he had anything to do with the death of his close friend, Prince," Johnson's attorney F. Clayton Tyler said in a statement.
In a separate development, a doctor who treated the musician in his final weeks has been fined for allegedly writing a prescription knowing it would be used by another person, the U.S. Attorney for Minnesota said in a statement.
The doctor, Michael T. Schulenberg, was fined $30,000 in a civil settlement with federal prosecutors over allegations that he violated the controlled substances act, Attorney Gregory Brooker said.
Brooker said Schulenberg was not the target of any criminal investigation in Prince's death. The physician's attorney said in a statement that Schulenberg worked to refer Prince to a treatment facility and he did not write any prescriptions with the intention that they would be used by the singer.
Prince's death shocked the world and led to a protracted battle among his siblings and half siblings over who would inherit his estate, estimated to be worth hundreds of millions of dollars in unreleased recordings and music rights.
On Thursday, Warner Bros. records and the singer's estate released the original version of Prince's 1984 song "Nothing Compares 2 U," along with a video featuring rehearsal footage, that has never been seen before, of the singer and his band The Revolution practicing their choreography that year.