Another mournful anniversary approaches: Superstar Prince died three years ago this week of an accidental opioid overdose at his Paisley Park compound in suburban Minneapolis.

We are never going to learn why. As the county district attorney announced at the two-year anniversary in April 2018, no one was charged with a crime in connection with his death because there was no evidence showing how he got fake Vicodin laced with fentanyl, a synthetic opioid 50 times stronger than heroin, and no evidence he even knew that's what it was.

Here's what we do know: Prince Rogers Nelson's death at age 57 has come to stand for hard lessons learned – about the nation's opioid crisis, about the challenges of achieving successful police investigations, about the downside of fame and the pitfalls of secrecy.

But the most obvious lesson of the Prince tragedy remains, and it is utterly prosaic: If you die without a will, you might leave behind confusion. Prince's assumed massive estate, believed to be worth hundreds of millions, is still unsettled, still not officially valued and still not disbursed to the heirs, his six siblings.

Instead, platoons of lawyers have been working on it for three years, racking up bills, arguing with each other, arguing with the heirs, arguing with consultants hired to advise on various estate matters, and filing blizzards of documents and paperwork with the Carver County probate court, which has made little progress in its mission to sort all this.

Puzzling out what is happening isn't easy because many of the documents in the case are heavily redacted. Has the value of the estate (once estimated at $200 million to $300 million) increased or decreased? Not clear.

It's not clear why the estate has not paid the hefty tax bills that were due to Uncle Sam and the state of Minnesota. A will might have been helpful in reducing the 40% tax bill to the federal government and the 16% bill for Minnesota.

The heirs' dissatisfaction with the estate administrators has grown, leading to their latest effort to gain more control over spending: So far, administrators have spent $45 million, including $10 million in legal fees, the heirs claim in documents.

It sounds egregious but it's not, says Judith T. Younger, a law professor at the University of Minnesota who teaches estate-and-trusts law. She says the messy state of the Prince estate is not uncommon. Sorting out these things takes time, she said.

"It’s not unusual (because) he had complicated assets, he had a lot of money, he didn’t leave a will – not that that would necessarily hasten the process," she says. "His assets are hard to manage. The heirs fight among themselves. But that's not unique, not in Minnesota or anywhere in the country."

Nor is it unusual that Prince would fail to prepare a will, she said. Like many people, rich or poor, famous or not, "He probably didn’t like to think about that."

Here's a status report on the estate:

The presiding judge: District Judge Kevin Eide remains in charge.

The estate administrators: There have been two. The first was Bremer Trust and now it's Comerica Bank & Trust. Each has employed multiple lawyers.

Comerica's lawyers declined to comment to USA TODAY on the status of the probate case as per its usual policy.

The heirs: Dozens of would-be claimants appeared after Prince died but the official heirs have been narrowed to six: Tyka Nelson, his full sister, and his half-siblings, Norrine Nelson, Sharon Nelson, John Nelson, Alfred Jackson and Omarr Baker.

The heirs' lawyers have not returned messages and the heirs themselves have done few interviews, as a group or as individuals. Tyka Nelson spoke out about a year after her brother's death on a British talk show to promote the 2017 "My Name Is Prince" exhibition at London’s O2 Arena; she said she had a premonition of his death three years earlier.

Paisley Park: Within months of Prince's death, administrators of his estate opened his white, aluminum-clad home/office/studio in Chanhassen, Minnesota, as a museum, managed by Graceland Holdings, which also runs Elvis Presley's Graceland. One of its aims was to provide revenue for the estate to help cover its tax bills.

Fans lined up in October 2016, and have been showing up ever since to tour his recording studios, admire the paintings of Prince on the walls, examine his stage costumes on display, and count his music trophies lining the hallways.

Celebration 2019, the annual commemoration of the anniversary of his death, gets underway for four days starting April 25, featuring live music and a long list of musical guests, panel discussions and special presentations on Prince’s legacy and influence as a composer, musician, producer, live performer and filmmaker.

The top-priced ticket for the four days is $1,100. That includes a concert event, "PRINCE: In Concert on the Big Screen," at The Armory in Minneapolis but doesn't count the hundreds of dollars fans can spend on Prince merchandise, including guitar picks, T-shirts, socks, gloves, umbrellas and the like.

“Paisley Park continues to draw visitors from all over the world and remains busy throughout the year,” says Joel Weinshanker, operating partner of Paisley Park management, in a statement to USA TODAY.

He said the museum is profitable and provides a revenue stream to the estate.

The music:

Last June, on what would have been Prince's 60th birthday, the estate and Warner Bros. said it would release a new album of the artist's material, "Piano & a Microphone 1983," in September 2018, which subsequently came out. The nine-track, 35-minute album features previously unreleased material of Prince at his piano in his home studio recorded in 1983.

In August 2018, the estate and Sony’s Legacy Recordings partnered to launch a first round of catalog digital releases with a set of 23 albums originally issued between 1995 and 2010, “Prince Anthology: 1995-2010.”

On April 13, in honor of Record Store Day, the estate and Legacy released the first commercial issue of Prince's "The Versace Experience: Prelude 2 Gold" cassette, a sought-after title among fans and collectors. The cassette, a gift to attendees at the designer's 1995 Paris Fashion Week show, was one of the rarest of Prince releases until it was recreated for Record Store Day.

There may be more unreleased material available for release in the future, but the estate won't say and neither will the record companies.

The Caribbean villa: After Prince's death, the estate quickly moved to sell land and buildingsPrince owned, most of it in the U.S. .

The most prominent luxury property, which might have brought in the most money, is Turtle Tail on Turks and Caicos – a sprawling 10,000-square-foot Caribbean villa that Prince bought for nearly $13 million in 2010.

At first, the Prince estate put the villa on the market for $12 million. It didn't sell. Next Premiere Estates, a luxury real-estate auction house, put it up for auction in July 2018, with no minimum bid except for a $100,000 registration fee. There is no record that it sold and it is not listed on the Premiere website.

Now what? Premiere did not return messages from USA TODAY about its next move regarding the villa.