Maria Puente

USA TODAY

Prompted by leaks, the Midwest Medical Examiner's Office in Minnesota released the long-awaited autopsy report on Prince Thursday, declaring the cause was accidental fentanyl toxicity.

Fentanyl is a powerful painkiller. The official cause of death thus bolsters previous reports that Prince died from a opioid overdose, and that investigators were examining how he might have obtained the drug.

The press release on the autopsy said that the medical examiner would not be making further comment, and the Carver County Sheriff's Office, which is leading the investigation of Prince's April 21 death, is continuing its inquiry.

Prince took fentanyl, a powerful painkiller that has caused surge in overdoses

The release, which came in a tweet by the medical examiner's office, showed a one-page summary of the autopsy report, which also included some details about how much Prince weighed at time of death (112 pounds); what he was wearing (black cap, black shirt, grey undershirt, black pants, black boxer briefs, black socks); his scars (left hip, right lower leg); and how the "injury" occurred.

"The decedent self-administered fentanyl."

According to the National Institute on Drug Abuse, fentanyl is a "powerful synthetic opiate analgesic similar to but more potent than morphine. It is typically used to treat patients with severe pain, or to manage pain after surgery. It is also sometimes used to treat people with chronic pain who are physically tolerant to opiates."

The DEA says fentanyl and its analogues come from China. Often it's mixed with heroin, to the point that field tests may indicate heroin when it’s actually fentanyl.

The autopsy tweet went out Thursday afternoon after the Associated Press reported, via an anonymous source, that Prince died of an opioid overdose.

Shortly after the AP's report, the Minneapolis Star-Tribune also quoted a "source with knowledge of the megastar’s death investigation" as saying that Prince died of an "overdose of painkillers."

The Sheriff's Office and the local Midwest Medical Examiner's Office, which conducted the autopsy, said immediately after the leaks Thursday that they had nothing new to report on the case. A few hours later, the tweet went out.

Prince's only full sister, Tyka Nelson, did not immediately respond to the autopsy report, but one of their half-siblings, Alfred Jackson, issued a statement through his lawyer, Frank Wheaton.

"On behalf of Alfred Jackson and the other family members and presumptive heirs, we are saddened by the reports that have been provided," the statement said. "However, we are thankful and gracious to the public for lending their never-ending support to the brilliant contributions in music that our brother gave to the world."

The official autopsy report on Prince, who was found dead and alone in an elevator at his Paisley Park compound in Carver County outside Minneapolis, has been long delayed. Conducted within days of his death, it is supposed to show why the 57-year-old superstar died.

The report has been delayed more than usual in similar cases of mysterious deaths; also, results of toxicology tests typically take several weeks at least to come back.

Investigators have focused on what roleprescription painkillers played in Prince's death, and if so, how he obtained them.

The investigation has been coordinated by the county Sheriff's Office, with help from the federal DEA and the U.S. Justice Department.

Although Prince was known to be an advocate of healthy living, who didn't drink or take illicit drugs, he may have suffered from debilitating pain from decades of vigorous concert performances in the high-heeled shoes he habitually wore.

Only days before he was found dead, Prince's staff had contacted a specialist in painkiller addiction to rescue Prince from what was described as a "grave medical emergency." The doctor, Howard Kornfeld, sent his son to meet with Prince; he arrived at Paisley Park and was present when Prince was found by his shocked staff.

Meanwhile, other local doctors were treating Prince or were planning to, including Michael Todd Schulenberg, a specialist in obstetrics, who also arrived at Paisley Park on the day Prince was found bearing the results of mysterious tests he had conducted on the singer.

And six days before his death, his private plane, enroute home after concerts in Atlanta, made an emergency landing in Moline, Ill., because he had fallen unconscious from an opioid overdose, according to reporting by the Minneapolis Star-Tribune. He was carried from the plane at the airport where paramedics gave him a shot of the opioid antidote Narcan. He was taken to a hospital, but left within a few hours against medical advice.

Investigators have said Prince was last seen the night before his death when an acquaintance dropped him off at Paisley Park about 8 p.m. following a visit to a drugstore. He was found at around 9:30 am the next day.

Aside from the lingering mystery of why he died and who might have played a role in his death, Prince's multi-million estate is in disarray because no will has been found.

A special administrator has been appointed to search for all his possible assets and potential heirs. These include a half-dozen previously known siblings and half-siblings, plus claims from a previously unknown half-sibling, descendants of a deceased half-sibling, and at least one man, a federal prison inmate, who says he's Prince's son as the product of a one-night stand.