The identity of a Twin Cities doctor who had been treating Prince several weeks before he died was revealed in a search warrant filed in Hennepin County District Court.

According to the warrant, Dr. Michael Todd Schulenberg, a family practitioner, had seen Prince twice before he was found in a Paisley Park elevator April 21. One visit occurred at the Chanhassen complex the day before Prince was found dead.

The warrant authorized the search and seizure of Prince’s medical records at North Memorial Medical Center in Robbinsdale.

Late Tuesday afternoon, local and federal investigators returned to Paisley Park, where they continued their work for more than five hours.

Schulenberg, 46, worked at North Memorial’s Minnetonka clinic, said health system spokeswoman Lesa Bader. However, the doctor no longer works with the health system. Bader declined to provide employment dates or disclose why Schulenberg no longer works there.

Carver County detective Chris Nelson said in a sworn statement used to obtain the warrant that Schulenberg had given a statement to deputies. Nelson wrote in the affidavit that Schulenberg told him that he had treated Prince on April 7 and on April 20. The doctor said he had arrived at Paisley Park the morning Prince was found in the elevator to deliver test results. The warrant does not describe the nature of the tests. It said that Schulenberg also told detectives that he had given Prince a prescription that was to be filled at a Walgreens.

The musician was to have performed a pair of concerts in Atlanta on April 7, but postponed those shows, blaming the flu.

A source with knowledge of the investigation told the Star Tribune on Friday that the doctor had been treating Prince for withdrawal symptoms from opioid addiction several weeks before his death. The source said the doctor did not prescribe opioids to the megastar.

The warrant, filed May 6, accidentally was left unsealed until Tuesday, when Carver County learned of the mistake and sent a copy of the order sealing it to the Hennepin County court administrator. The Star Tribune obtained a copy.

Schulenberg could not be reached for comment Tuesday. A review of his medical license shows no disciplinary action against the physician, who was trained at Oregon Health & Science University and who has board certification in family medicine.

His attorney, Amy Conners, declined to comment Tuesday, citing the requirement that patient information be kept confidential.

Prince reportedly was seeking treatment for addiction to painkillers in the weeks before his death.

Representatives for the pop star reached out on April 20 to a California physician, Dr. Howard Kornfeld, who dispatched his son to meet with Prince the next day, along with another doctor who was federally certified to prescribe a medication, buprenorphine, which is used in the treatment of opioid addiction.

Schulenberg is not on the list maintained by the U.S. Food and Drug Administration of practitioners who can prescribe buprenorphine. The second Minnesota physician, who has not been publicly identified, had cleared his morning calendar to evaluate Prince on the day his body was found, the source said. The appointment never took place.

The warrant also reveals that Kirk Anthony Johnson — a close associate of Prince’s who manages Paisley Park — was present when detectives arrived at the death scene. The Star Tribune has reported that two staffers were present, along with Kornfeld’s son, Andrew, when Prince’s body was found.

The affidavit says that detective Christina Wagner interviewed Johnson, who said that Prince had been treated in the Ridgeview health system for an undescribed illness in 2014 or 2015.

Johnson could not be reached for comment. His attorney, F. Clayton Tyler, declined to comment Tuesday.

Prescription data

Meanwhile, investigators are looking into the means by which Prince received prescription opioids, which are narcotics subject to additional federal regulation.

Prescriptions of opioids are reported to the Minnesota Board of Pharmacy as part of the state’s monitoring of addicts who are obtaining the drugs from multiple practitioners. While these records can be obtained by law enforcement authorities under a search warrant, the board’s executive director, Cody Wiberg, said Tuesday that his office has no such warrants in its possession.

However, medical examiners can review the prescribing data without warrants on patients whose deaths they are investigating. So it is possible that the state opioid prescribing data has been consulted.

The Midwest Medical Examiner’s Office in Anoka is conducting the investigation to determine how Prince died. Results are pending. The Carver County Sheriff’s Office has said that neither foul play nor suicide are suspected.

Shortly before 6 p.m., about a half-dozen unmarked cars were parked at Paisley Park. Private security officers also walked the perimeter and were stationed at the gates. Over the next several hours, the security crew waved cars into and out of the grounds through a main gate.

As the officers worked, dozens of people stood outside Paisley Park’s security fence to take photos of the flowers, balloons and purple memorabilia left in Prince’s honor.

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