A Twin Cities physician had been treating Prince for withdrawal symptoms from his opioid addiction several weeks before he collapsed April 21 in a Paisley Park elevator, according to a source with knowledge of the investigation.

The physician, who is the doctor for Prince’s longtime friend Kirk Johnson, had been working with the megastar before the April 15 opioid overdose that took place while Prince was flying home from a pair of performances in Atlanta. Johnson, a personal trainer who ran Paisley Park and played drums for Prince, recommended the doctor, the source said.

The source, and another person with knowledge of the investigation, said in separate interviews Friday that the physician did not prescribe opioids to Prince. The doctor has not been publicly identified.

Still, Prince’s inner circle became so concerned about his health that one of his representatives in California reached out to Dr. Howard Kornfeld, a noted pain and addiction specialist in Mill Valley, Calif., one of the sources told the Star Tribune.

Kornfeld got that call the evening of April 20 and learned that the physician who had been treating Prince had just seen him, the source said. That doctor reported that he had visited Prince at Paisley Park and that the artist was in serious but stable condition that night.

Kornfeld dispatched his son, Andrew Kornfeld, who worked with his father, to meet with Prince and a second Minnesota doctor — certified to prescribe an opioid addiction treatment medication that Dr. Kornfeld uses — the following day. That Minnesota doctor, who also hasn’t been publicly identified, had cleared his calendar for the morning of April 21 so that Prince could go to his office for an independent evaluation, the source said.

The meeting never took place. Andrew Kornfeld and two of Prince’s staff members found his body in the elevator about 9:40 a.m. Andrew Kornfeld called 911 because the others, who haven’t been publicly identified, were too distraught.

Ryan Garry, an attorney for one of them, declined to comment Friday, as did William Mauzy, who represents the Kornfelds.

Legal questions surface

As the death investigation continues and the public awaits toxicology results, the attempted emergency delivery of the medication to treat Prince’s addiction is raising medical ethics and legal questions.

Mauzy said at a recent news conference that Dr. Kornfeld had sent his son, a pre-med student, on an overnight flight to Minnesota with a starter dose of buprenorphine. The controlled substance is commonly used to treat opioid addiction.

Dr. Kornfeld, who is licensed in California and federally registered to prescribe controlled substances, would have had the authority to prescribe medication to Prince in Minnesota. However, he or an associate would have needed to conduct an in-person exam before prescribing or administering a controlled substance such as buprenorphine.

“Controlled substances require that there has been an in-person examination of the patient — either when the prescription is issued or at some point in the past,” said Cody Wiberg, executive director of the Minnesota Board of Pharmacy, in an e-mail. “There are several ways in which the exam can be completed — by the prescriber, by another practitioner working in the same practice as the current prescriber, etc.”

That appears to be what Dr. Kornfeld had in mind by arranging an appointment with the second Minnesota doctor for April 21.

One question is whether the younger Kornfeld had the legal authority to carry a controlled substance from California to Minnesota. Andrew Kornfeld is listed as a practice consultant for his father’s Recovery Without Walls treatment center and has training in psychology and neuroscience — though he is not a licensed practitioner.

Dr. Kornfeld also does not have a Minnesota medical license, though Mauzy has said that the plan was for Prince to travel to California to be placed under his care. Ultimately, he said, Dr. Kornfeld never got the chance to even speak with Prince, let alone treat him.

Buprenorphine and a brand-name version, known as Suboxone, are difficult to access in Minnesota, where only 120 physicians have completed the necessary certification training to prescribe the drug.

Mauzy has declined to comment on whether Andrew Kornfeld had legal protection to carry the medication to a licensed physician. He said he believes Andrew Kornfeld is protected from any charges by a Minnesota law that generally shields anyone seeking medical assistance for a person overdosing on opioids.

Minnesota’s good Samaritan law allows people to render aid in a medical emergency. The law states that “reasonable assistance may include obtaining or attempting to obtain aid from law enforcement or medical personnel.”

Whether the Minnesota Board of Medical Practice is looking into Dr. Kornfeld’s actions is unknown. The board doesn’t acknowledge investigations of any doctors until it takes disciplinary action against them.

Staff writers Pam Louwagie and Emma Nelson contributed to this report.