No criminal charges will be filed in Prince’s death, and evidence shows that the musician thought he was taking a common painkiller instead of a counterfeit pill containing the fentanyl that killed him, a Minnesota prosecutor said Thursday.

Carver County Attorney Mark Metz said investigators found no evidence of “any sinister motive” but that some associates had sought to protect Prince’s privacy. The lack of criminal charges does not mean that associates did not enable the singer’s habits, Metz said, but there’s no evidence any of them knew about the fentanyl.

“We do not have evidence that a specific person provided fentanyl to Prince,” he said.

Metz’s announcement came just hours after documents revealed that a doctor who was accused of illegally prescribing an opioid for Prince agreed to pay $30,000 to settle a civil violation of a federal drug law. Dr. Michael Todd Schulenberg allegedly wrote a prescription for oxycodone in the name of Prince’s bodyguard, intending for the potent painkiller to go Prince. That prescription was not linked to Prince’s death.

Prince was 57 when he was found alone and unresponsive in an elevator at his Paisley Park studio compound on April 21, 2016. His death sparked a national outpouring of grief and prompted a joint investigation by Carver County and federal authorities.

An autopsy found he died of an accidental overdose of fentanyl, a synthetic opioid 50 times more powerful than heroin. State and federal authorities have been investigating the source of the fentanyl for nearly two years. Metz’s announcement effectively closed the case.

After the announcement, the U.S. Attorney’s Office said that federal prosecutors had no credible evidence that would lead to federal criminal charges. A law enforcement official close to the investigation told The Associated Press that the federal investigation is now inactive unless new information emerges. The official spoke on condition of anonymity because the federal case remains open.

Federal prosecutors and the Drug Enforcement Administration alleged Schulenberg, a family physician who saw Prince at least twice before he died, violated the Controlled Substances Act when he wrote a prescription in the name of someone else on April 14, 2016.

The settlement, dated Monday, does not name Prince or make any references to the Prince investigation. However, search warrants say Schulenberg told authorities he prescribed oxycodone for Prince under the name of his bodyguard and close friend, Kirk Johnson, “for Prince’s privacy.”

Schulenberg’s attorney, Amy Conners, has disputed that and did so again Thursday, saying that Schulenberg settled the case to avoid the expense and uncertain outcome of litigation.

Oxycodone, the generic name for the active ingredient in OxyContin, was not listed as a cause of Prince’s death. But it is part of a family of painkillers driving the nation’s addiction and overdose epidemic, according to the Centers for Disease Control and Prevention. Nearly 2 million Americans abused or were addicted to prescription opioids, including oxycodone, in 2014.

A laboratory report obtained by The Associated Press noted that one of the pills found in a prescription bottle in Paisley Park that bore Johnson’s name tested positive for oxycodone.

“Doctors are trusted medical professionals and, in the midst of our opioid crisis, they must be part of the solution,” U.S. Attorney Greg Brooker said in a statement Thursday.

The settlement noted that the agreement “is neither an admission of facts nor liability by Dr. Schulenberg.” And in a separate letter to Schulenberg’s attorneys, prosecutors said Schulenberg is not currently a target of any criminal investigation.

Under the settlement, Schulenberg also agreed to stricter requirements for logging and reporting his prescriptions of controlled substances for two years, and to give the DEA access to those records.

It’s illegal for a doctor to write a prescription for someone under another person’s name. Doctors convicted of doing so could lose their DEA registration, meaning they could no longer prescribe controlled substances. They could also face discipline from their state medical board.

The settlement says the DEA will not revoke Schulenberg’s registration, unless he does not comply. It’s unclear whether the state medical board will take action. His license is currently active, and he has no disciplinary action against him.

A confidential toxicology report obtained by the AP in March showed high concentrations of fentanyl in the singer’s blood, liver and stomach. The concentration of fentanyl in Prince’s blood alone was 67.8 micrograms per liter, which outside experts called “exceedingly high.”

Prince did not have a prescription for fentanyl. Search warrants unsealed about a year after he died showed that authorities searched his home, cellphone records of associates and his email accounts to try to determine how he got the drug. Authorities found numerous pills in various containers stashed around Prince’s home, including some counterfeit pills that contained fentanyl.

While many who knew Prince over the years said he had a reputation for clean living, some said he also struggled with pain after years of intense performing. Documents unsealed last year paint a picture of a man struggling with an addiction to prescription opioids and withdrawal symptoms. The papers also show there were efforts to get him help.

Just six days before he died, Prince passed out on a flight, and the private plane made an emergency stop in Moline, Illinois. The musician had to be revived with two doses of a drug that reverses the effects of an opioid overdose.

The day before his death, Paisley Park staffers contacted California addiction specialist Dr. Howard Kornfeld. The doctor sent his son, Andrew, to Minnesota that night, and the younger Kornfeld was among those who found Prince’s body. Andrew Kornfeld was carrying buprenorphine, a medication that can be used to help treat opioid addiction.