Prince had been seeking treatment for opioid and cocaine addictions just before he died. Although an official cause of death still has yet to be determined, an autopsy last week revealed that Prince had Percocet in his system when he died, and Minnesota authorities have launched a criminal investigation into doctors who might have prescribed him drugs.

According to a search warrant executed for the late musician’s medical records, a Minneapolis-area doctor had seen Prince twice in the month before his death, including the day before he died. As The LA Times reports, Dr. Michael Todd Schulenberg, who specializes in family medicine, treated Prince on 4/7 and 4/20. He told investigators that he prescribed medication to Prince, although what medication and whether or not Prince filled the prescription remains unclear. The doctor was also reportedly at Paisley Park to deliver test results on the morning that Prince was found dead.

The search warrant was executed last week at the North Memorial Medical Center, where Schulenberg worked as a primary care physician. A spokeswoman for the North Memorial Healthcare system said that Schulenberg no longer works at the hospital but was unable to provide more details about when and why he left, citing policies that protect confidential information regarding both employees and patients.

Carver County Deputy Sheriff Jason Kamerud said that the warrant was supposed to have been filed under seal and he could not comment on its contents. The investigation is still ongoing.