CHICAGO (AP) — The official told The Associated Press investigators also want to know if Dr. Howard Kornfeld and son Andrew Kornfeld had a longer-term medical relationship with Prince. Neither is accused of wrongdoing.

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The law enforcement official had been briefed on the investigation and spoke on condition of anonymity because he wasn't authorized to speak to the media.

The Kornfelds' attorney, William Mauzy, said Prince's staff called Howard Kornfeld on April 20. He sent his son on an overnight flight with the drug buprenorphine. Andrew Kornfeld found Prince unresponsive and did not administer the drug.

Before finding Prince, doctor's son taught drug users to surf

Andrew Kornfeld's red-eye flight to bring a prescription drug to Prince has been described by his attorney as a "lifesaving mission" to persuade the superstar to start treatment for addiction.

Instead, the young Californian found Prince collapsed in an elevator, perhaps already dead.

The 26-year-old son of an addiction and pain doctor helped in his father's medical practice by teaching young drug users in recovery to surf. In college, he studied neuroscience and developed a fascination with consciousness and psychedelic drugs such as LSD.

Jim Fadiman is a psychologist who popularized the notion of using micro-doses of LSD to enhance workplace productivity. He considers the younger Kornfeld "brilliant."

Since his connection with Prince became known, Andrew Kornfeld has avoided talking publicly about the musician's death.

Judge in Prince's estate case authorizes DNA testing

CHASKA, Minn. (AP) — The judge overseeing the Prince estate case has authorized genetic testing on a sample of his blood in case it's necessary to determine who's entitled to shares of the estate.

Carver County District Judge Kevin Eide on Friday granted a request by the special administrator overseeing the estate, Bremer Trust, to hire DNA Diagnostics Center to perform the genetic testing on a blood sample now held by the medical examiner's office that conducted the autopsy on Prince.

Prince died April 21 at his home in suburban Minneapolis. The cause remains under investigation.

In his order, the judge says he's "recognizing that parentage issues might arise" in the administration of Prince's estate. He's authorized the medical examiner to release the blood sample to the testing laboratory.