A mural honoring the late rock star Prince adorns a building in the Uptown area of Minneapolis Thursday, April 28, 2016, Prince died last week at his Paisley Park home at the age of 57. An investigation into his death continues. (AP Photo/Jim Mone)

A mural honoring the late rock star Prince adorns a building in the Uptown area of Minneapolis Thursday, April 28, 2016, Prince died last week at his Paisley Park home at the age of 57. An investigation into his death continues. (AP Photo/Jim Mone)

MINNEAPOLIS (AP) _ Authorities are investigating whether Prince died from an overdose and whether a doctor was prescribing drugs for the musician in the weeks before he was found dead at his suburban Minneapolis home. A guide to the latest developments:

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INQUIRY INTO EMERGENCY LANDING

Questions about Prince’s health surfaced April 15, when his private plane made an emergency stop in Moline, Illinois. He was found unconscious aboard the aircraft, according to a law enforcement official who was briefed on the investigation and spoke to The Associated Press. The official spoke on condition of anonymity because he was not authorized to speak to the media.

While the plane was on the tarmac, the person said, first-responders gave Prince a shot of Narcan, an antidote that is used to reverse suspected opioid overdoses.

At the time, Prince was returning to Minneapolis following a performance in Atlanta. The official said investigators are looking at whether he overdosed on the flight and whether an overdose killed him. One possibility is the powerful painkiller Percocet or something similar, the official said.

Investigators also want to know whether a doctor was on the plane and whether any drugs were aboard the aircraft or at Prince’s Minnesota house.

While the investigation is far from complete, the mention of a doctor calls to mind other celebrity deaths, including Michael Jackson’s. Jackson’s physician, Conrad Murray, was convicted of involuntary manslaughter for his role in prescribing a powerful anesthetic that contributed to the pop star’s death in 2009.

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A SEARCH OF STAR’S HOME

A second law enforcement official told AP that prescription drugs were discovered at Prince’s home when the musician was found dead on April 21.

That official also spoke on condition of anonymity because the person was not authorized to speak about the ongoing investigation. The official did not elaborate.

Prince’s Paisley Park home and studio were searched on the same day he died. The warrant and accompanying documents were filed Thursday under seal at the request of investigators who said it would hamper their investigation if the contents were public.

An affidavit in support of sealing the warrant warned that disclosing details in the warrant could cause “the search or related searches to be unsuccessful” and risk injury to innocent people.

The person who signed that affidavit, Carver County Chief Deputy Jason Kamerud, declined to comment Thursday on the reports of drugs found at Paisley Park, and told AP that he disputed reports by several media outlets that investigators had asked the U.S. Drug Enforcement Administration for help.

“We have not asked them for help or asked them to be a part of the investigation,” Kamerud said. “We might contact them to help us, but that hasn’t happened.”

He said authorities did not have the medical examiner’s report yet and did not know “to what extent pharmaceuticals could be a part of this.”

An autopsy has been performed, but results are not expected for three to four weeks.

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OTHER HEALTH COMPLAINTS, CANCELED CONCERTS

Prince’s death came two weeks after he canceled concerts in Atlanta, saying he wasn’t feeling well. He played a pair of makeup shows April 14 in that city. Prince was scheduled to perform two shows in St. Louis but canceled them shortly before his death due to health concerns.

Longtime friend and collaborator Sheila E. has told the AP that Prince had physical problems from his performances, citing hip and knee trouble that she said came from years of jumping off risers and stage speakers in heels.