A New Handbook, a Dutch Trial, and the Mona Lisa on Stage

A new Research Handbook on Art, Culture and Heritage Law has just been published by Edward Elgar, co-edited by Sophie Vigneron, Janet Ulph, and Antoinette Maget Dominicé. The volume is a substantial one — 682 pages — and it brings together an impressive range of scholars to examine art, culture, and heritage law through four broad challenges: sustainable development, intergenerational equity, decolonisation, and cultural rights. The publisher describes it as both interdisciplinary and practical, with chapters addressing the definition, protection, and contestation of cultural heritage, alongside subjects such as provenance research, repatriation, trafficking in peacetime, wartime looting, and the intentional destruction of heritage.

The table of contents alone gives a good sense of the range. There are chapters by Patty Gerstenblith on the 1970 UNESCO Convention, Emma Cunliffe on the 1954 Hague Convention, Anne-Marie Carstens on international cultural heritage crimes, Sophia Labadi on world heritage and sustainable development, Neil Brodie on EU Regulation 2019/880 on the import of cultural goods, Emily Peacock and Donna Yates on the online antiquities trade, Evelien Campfens on cross-border restitution, and Andrea Wallace, Francesca Farmer and Mathilde Pavis on restitution beyond the object. My own contribution is a chapter on “Cultural heritage law in the United States.”

In a field that often splinters into separate conversations — market regulation over here, armed conflict there, restitution somewhere else — there is real value in a volume that tries to gather these debates into one place.

For those interested, the publisher’s page is here: Research Handbook on Art, Culture and Heritage Law.

The more immediate news item is the start of the Dutch trial over the theft of major Romanian gold artefacts from the Drents Museum, including the celebrated Coțofenești Helmet, a 5th-century BCE object, and three Dacian gold bracelets. Dutch prosecutors have reportedly sought sentences ranging from 44 to 66 months, and specifically asked for three years and eight months for Jan B. (21) and Douglas Chesley W. (37) after plea agreements aimed at securing the return of the helmet and two of the bracelets.

That cooperation matters. Dutch prosecutors said earlier this month that the Coțofenești Helmet and two of the three bracelets were recovered after discussions with defence counsel and agreements with the suspects; the Public Prosecution Service made clear that a condition of those agreements was the return of the artefacts. Reuters likewise reported that the recovery came with the help of information from the suspected thieves. One bracelet is still missing.

The case is a useful reminder that criminal prosecutions in cultural objects are often doing more than assigning blame after the fact. Sometimes they are structured, explicitly, to recover objects first and punish later. That may be unsatisfying in one sense — especially where the penalties sought do not seem especially severe given the cultural stakes — but it also reflects a hard truth: once an object like this disappears, the first priority is often simply getting it back before it is damaged, dispersed, or lost entirely. In this instance, the helmet was recovered slightly dented, though museum officials say it can be restored.

And then, because the art world never misses a chance to become faintly ridiculous just when things have turned serious, there is this: Andrew Lloyd Webber is apparently working on a musical about the theft of the Mona Lisa. According to The Art Newspaper, the project is based on the 1911 theft by Louvre employee Vincenzo Peruggia, who removed the painting and it later resurfaced in Italy. Lloyd Webber described it as “the true story” of how the painting disappeared for roughly three years and ended up in Italy.

Sophie Vigneron et al., Research Handbook on Art, Culture and Heritage Law (Edward Elgar Publishing, Incorporated Mar. 2026).

Stealing the Show: Mona Lisa Heist Inspires Andrew Lloyd Webber Musical, The Art Newspaper – International art news and events, https://www.theartnewspaper.com/2026/04/13/stealing-the-show-mona-lisa-heist-inspires-andrew-lloyd-webber-musical (last visited Apr. 14, 2026).

Dutch Prosecutors Urge Long Jail Terms for Romanian Helmet Theft, France 24, https://www.france24.com/en/live-news/20260414-dutch-trial-over-theft-of-golden-romanian-helmet-begins (last visited Apr. 14, 2026).

Security, Spectacle, and Return

It has been an oddly revealing week for cultural heritage.

On one end, Dutch officials unveiled the recovered Coțofenești helmet and two gold bracelets at a press conference in Assen, flanked by heavily armed officers in balaclavas. The helmet, stolen from the Drents Museum in January 2025 while on loan from Romania, was recovered with minor damage; though one bracelet remains missing. The recovery appears to have come as part of an agreement with suspects ahead of trial.

A Geto-Dacian helmet dating from the first half of the 4th century BC, uncovered by chance. View from the front.
By © Radu Oltean / Wikimedia Commons, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=14615152

On the other end, just days earlier, thieves entered the Magnani-Rocca Foundation near Parma and, in about three minutes, made off with works by Renoir, Cézanne, and Matisse. Reports describe a fast, organized raid by four men who forced entry and targeted highly recognizable names.

And then, in Zurich, Switzerland quietly transferred ownership of 28 Benin Bronzes from three museums, with 18 expected to travel physically to Nigeria in June. That return followed provenance research and was framed, quite rightly, as another step toward reuniting Nigeria with material taken in the 1897 British plunder of Benin.

Three stories, one week, and each says something slightly different about how the cultural heritage world performs security, legitimacy, and justice.

The Dutch press conference was the most visually obvious example. The object had been recovered. Great! That part matters most. But the staging mattered too. Armed guards. Masks. Cloth lift. The careful unveiling of a rescued national treasure. It was a display of regained control. One could almost hear the subtext: yes, it was stolen, but look how seriously we take it now.

That is what struck Donna Yates so clearly in her reaction to the event: the oddity of the whole performance. The recovery of a cultural object becomes not just an announcement, but a kind of theatrical rebuttal to the earlier embarrassment. The state is not merely returning the object; it is staging authority. And perhaps staging reassurance too.

The Italian theft, by contrast, stripped away the theatre. There is no ceremonial dignity in a three-minute smash-and-grab. Only a broken entry point, a short timeline, and the uncomfortable reminder that museums remain vulnerable to ordinary criminals with planning, nerve, and a few minutes to spare. Anthony Amore’s point is useful here: three minutes is not some cinematic anomaly. It sits squarely within the normal range for many museum thefts. That should worry people more than the headline itself.

The most important lesson from Parma may be the least glamorous one. Famous art is easier to steal than to monetize as Anja Shortland details. Freshly stolen museum objects are extraordinarily difficult to sell on the legitimate market because dealers, auction houses, and registries check title, provenance, and stolen-art databases. That does not mean theft makes no economic sense; it means the economic logic is usually murkier than the movies suggest. These works may be held, moved through criminal networks, used as bargaining chips, or dangled in hopes of some later leverage. The hard part is not the theft. The hard part is cashing out.

And that, in turn, makes the Dutch recovery more interesting. If a stolen object can later become useful in plea bargaining or sentence reduction, then it acquires a kind of underworld value quite apart from its cultural value. That is not a comforting thought. The helmet is priceless to Romania; it may also have become useful to suspects once prosecutors made clear that recovery would matter.

Then there is the Swiss Benin return, which points in a different direction entirely. No broken door, no emergency unveiling. Instead, a transfer of ownership after provenance work, a public ceremony, and a clear acknowledgment that access to cultural heritage means more than a paper change in title.

But even here, where the moral and historical case is much clearer, ceremony still does important work. Returns like this are also public performances—just of a more attractive kind. They signal fairness, accountability, and institutional maturity. They tell a story not about how we have secured this object, but about we are finally doing the right thing. Switzerland’s transfer of 28 objects, and the expectation that 18 will physically move to Nigeria in June, is meaningful precisely because it joins symbolism to substance.

Still, the Swiss story also comes with a caution. Returns create expectations. Nigeria’s National Commission for Museums and Monuments has had notable success in securing repatriations, but it now faces the harder question of display, stewardship, resources, and internal politics. Justice is not finished when the ceremony ends. Sometimes that is where the real work starts.

Taken together, these stories reveal a familiar pattern in cultural heritage disputes. We are very good at paying attention to dramatic moments: the theft, the raid, the recovery, the unveiling, the handover. We are less good at attending to the quieter work in between: preventive security, provenance research, institutional due diligence, funding, and conservation. Yet that unglamorous middle is where most of the work actually happens.

In Assen, security was performed after failure. In Parma, failure arrived in three minutes. In Zurich, legitimacy was sought through return. None of those performances are trivial. But none should distract from the underlying question either: are institutions actually getting better at protecting and returning cultural objects, or are they just getting better at staging the moment?

Anthony Amore, The Italian Job – A Profile, Big Security, https://anthonyamore.substack.com/p/the-italian-job-a-profile (last visited Apr. 3, 2026).

Eileen Kinsella, Experts Break Down the Brazen $10 Million Museum Theft in Italy, Artnet News, https://news.artnet.com/art-world/magnani-rocca-foundation-heist-experts-2761113, archived at https://perma.cc/9M2G-CZJY (last visited Apr. 3, 2026).

Senay Boztas, ‘A Wow Moment’: Ancient Romanian Gold Helmet Returned in Plea Deal with Theft Suspects, the Guardian, https://www.theguardian.com/artanddesign/2026/apr/02/stolen-romanian-gold-helmet-recovered-netherlands, archived at https://perma.cc/74V4-PWVR (last visited Apr. 3, 2026).

Claire Moses, Ancient Artifacts Stolen in Dutch Museum Heist Are Recovered, The New York Times (Apr. 2, 2026), https://www.nytimes.com/2026/04/02/world/europe/museum-heist-netherlands-helmet-romania.html.

Barnaby Phillips, Switzerland Returns Benin Bronzes, Institute of Art and Law (Apr. 2, 2026), https://ial.uk.com/switzerland-returns-benin-bronzes/, archived at https://perma.cc/2F52-DU6R.

Anja Shortland, Selling Stolen Art is Tricky, so Why Even Bother Heisting It? An Expert Explains, The Conversation, https://theconversation.com/selling-stolen-art-is-tricky-so-why-even-bother-heisting-it-an-expert-explains-279700, archived at https://perma.cc/D9EX-5R2M (last visited Apr. 3, 2026).

Ali Watkins & Josephine de La Bruyère, Renoir, Cézanne and Matisse Artworks Are Stolen in 3-Minute Museum Heist, Police Say, The New York Times (Mar. 30, 2026), https://www.nytimes.com/2026/03/30/world/europe/parma-art-heist-renoir-matisse-cezanne-italy.html.

Donna Yates, Performance of Security at the Drents Museum Helmet Return Press Conference, Anonymous Swiss Collector (Apr. 2, 2026), https://www.anonymousswisscollector.com/2026/04/performance-of-security-at-the-drents-museum-helmet-return-press-conference.html, archived at https://perma.cc/6X68-JZ6J.

Renoir, Cézanne and Matisse Works Stolen in ‘Three-Minute’ Italian Museum Heist, The Art Newspaper – International art news and events, https://www.theartnewspaper.com/2026/03/30/renoir-cezanne-matisse-works-stolen-in-three-minute-italian-museum-heist, archived at https://perma.cc/563Y-H7LT (last visited Apr. 3, 2026).

This is how you write about art theft

“The Parsonage Garden at Nuenen in Spring”, Vincent van Gogh; stolen from the Singer Laren Museum in March amid the pandemic.
Octave Durham, who stole two works from the Van Gogh Museum in Amsterdam told Siegal “My number one rule is talk smooth, be cool, have a fast car and never touch anyone”.

Nina Siegal has written a terrific story on that recent theft of a work by Vincent van Gogh from the Singer Laren Museum. That theft was likely a quick crime of opportunity, as the thief must have underestimated the chances of turning that work into a future profit. That’s the big takeaway from the well-reasoned piece by Siegal, who gets a former thief Octave Durham, Ursula Weitzel the lead public prosecutor for art crimes for the Netherlands Public Prosecution Service, and the art theft investigator Arthur Brand to reveal the hard truths of art theft: the art itself is a silly thing to steal.

As ‘Okkie’ Durham is quoted:

“I just did it because I saw the opportunity,” Mr. Durham said. He noticed a window at the museum that he thought would be easy to smash. “I didn’t have a buyer before I did it,” he said. “I just thought I can either sell them, or if I have a problem I can negotiate with the paintings.”

As Weitzel points out: “Unless it’s a crime of passion, usually the motive is to make money,” she said. “It’s as simple as that. People don’t steal it because they want to hang it on the wall. That kind of theft for pride or status, I haven’t seen that. It’s usually for money. Or, for safekeeping, in the event that it may be necessary.” And the hard truth of the difficulty in seeing a profit off of a theft means those stolen works stay hidden with a very low return on the market value of the work according to Brand.

Nina Siegal, What Do You Do With a Stolen van Gogh? This Thief Knows, The New York Times, May 27, 2020, https://www.nytimes.com/2020/05/27/arts/design/van-gogh-stolen.html.

Theft of a Van Gogh at the Singer Laren Museum

The Parsonage Garden at Nuenen in Spring 1884, Vincent Van Gogh

In the early hours of Monday March 30, thieves broke the front glass window of the Singer Laren museum east of Amsterdam. The thief or thieves stole an early work by Vincent Van Gogh. In a press conference on Monday annnouncing the theft Singer Laren museum director Jan Rudolph de Lorm expressed shock and sadness:

I’m shocked and unbelievably annoyed that this has happened . . . . This beautiful and moving painting by one of our greatest artists stolen – removed from the community . . . . It is very bad for the Groninger Museum, it is very bad for the Singer, but it is terrible for us all because art exists to be seen and shared by us, the community, to enjoy to draw inspiration from and to draw comfort from, especially in these difficult times.

The Dutch Police announced that the work is only 25×57 centimeters, oil on paper, and was one of Van Gogh’s early works before he moved to southern France. The thief or thieves smashed the glass door entrance and set off the alarm, but were able to steal the small work before police arrived.

Most art thieves are awful people; but those responsible for this theft are especially vile. Art thefts seem to cluster around holidays and periods of inactivity. As the world looks increasingly to starve the Coronavirus of new hosts, and more and more people stay home, art museums are closed. And they are at increased risk from thefts.

Dutch museum says van Gogh painting stolen in overnight raid, AP NEWS (Mar. 30, 2020), https://apnews.com/e635b833e60dfcb01351752976d818df.

Vincent van Gogh painting stolen from Netherlands museum, The Independent (Mar. 30, 2020), https://www.independent.co.uk/news/world/europe/vincent-van-gogh-painting-stolen-singer-laren-museum-netherlands-a9435666.html.

AP Reveals U.S. Investigation of Missing Venezuelan Artworks

An image of the Avila mountain by Manuel Cabre.

The AP has a fascinating story on the investigation of missing artworks that may have been taken from the Venezuelan ambassador’s residence in Washington. At present only three works are confirmed missing, but the piece hints that others might be missing as well. The uneasy economic and political situation in Venezuela may make conditions ripe for officials and others to make off with valuable state works. Carlos Vecchio, an exiled Venezuelan politician told the AP:

This is likely just the tip of the iceberg . . . . If this is what they’ve managed to do with some artwork at a single diplomatic mission, you can imagine what they’ve done inside Venezuela.

To borrow a tired phrase, art and the status of culture is so often a canary in the coal mine. The AP story notes that:

A New York-based art dealer said that in 2012 he toured the vaults of the agency’s headquarters in downtown Caracas in the company of its vice president, who proposed unloading sculptures and paintings by well-known Spanish artists Baltasar Lobo and Manuel Valdes in exchange for kickbacks. The collection was commercially attractive but poorly cared for, with canvasses piling up on emergency stairwells and exposed to sunlight, said the dealer, who spoke on condition of anonymity for fear of reprisals from Venezuelan government officials. He showed The Associated Press photos on his cell phone of some of the works on offer.
Even in better times Venezuela was ripe for some high-stakes museum heists. A painting by the French artist Henri Matisse, “Odalisque in Red Pants,” went missing around two decades ago from the Museum of Contemporary Art and was replaced by a badly-produced fake. The original was discovered in 2012 in a Miami hotel room and returned by the FBI to Venezuela’s government two years later. A Cuban man and a Mexican woman were arrested trying to sell the painting to undercover FBI agents in Miami Beach, but who was behind the theft, and exactly when it even took place, remains a mystery.
Today, the museum, which boasted the largest collection of contemporary art in Latin America when it was founded in the 1970s, is a shadow of its former glory. Galleries are mostly empty, security guards nowhere to be found and the artwork exposed to the tropical heat after the air conditioning units were damaged in the frequent blackouts ravaging the capital.
One of the museum’s highlights, a collection of 147 works by Picasso, is no longer on permanent display, although it did make a brief appearance at a rare show last year titled “Comrade Picasso” that stressed the Spanish artist’s communist activism. For the museum’s once loyal promoters, who were removed by Chávez in a cultural purge 18 years ago, it is a recent photo that went viral on social media of a bucket collecting water from a leaky gallery ceiling that best sums up the current state of neglect.
A few blocks away, at the century-old Museum of Fine Arts, the situation is even more desperate. Only about a third of its 18 galleries are open to the public; the rest have been closed for months for renovations, although there’s no sign any are taking place.

Joshua Goodman, US helping Venezuela’s Guaido track stolen art, AP NEWS (Sept. 19, 2019), https://apnews.com/b19c195aca5445918e48142154dbc77c [https://perma.cc/YB23-3X42].

Italy’s Carabinieri Outwits Art Thieves

The Crucifixion, by Pieter Bruegel the Younger, a copy of a similar work by his father (wikipedia commons)

Italy’s art squad, the Carabinieri Tutela Patrimonio Culturale, are the pre-eminent art police squad for a reason.

Thieves hoping to steal this work learned that lesson the hard way last week when they attempted to steal this work of art from a baroque church (Chiesa di Santa Maria Maddalena) in Castelnuovo Magra in Liguria. Working from information that a theft was imminent, the Carabinieri and only a handful of the residents of the town orchestrated and elaborate switch.

They swapped the real painting out for a copy, and that’s what the thieves stole.

The thieves now have a near-worthless copy, and the painting is still safe in storage.

Daniele Montebello, the mayor of the town which has a population of 8,500, said “The original painting was replaced by a copy more than a month ago . . . We were hearing rumours that someone wanted to steal it, so the Carabinieri brought in the fake and installed security cameras.”

Parish Priest Fr. Alessandro Chintaretto, who was reportedly napping nearby when the theft took place, expressed relief the original is safe: “It is a work of rare beauty which expresses a moment of profound faith . . . ”. 

A Profile of Vjeran Tomic


Georges Braque, 1906, L’Olivier près de l’Estaque (The Olive tree near l’Estaque)

In 2010 Vjeran Tomic managed to pull off an improbable heist. During a series of late night visits, he managed to make off with five important works from the Musée d’Art Moderne, including Pastoral by Henri Matisse, Woman with a Fan by Modigliani, Pablo Picasso’s Dove with Green Peas, and George Braques Olive Tree near Estaque. These works were always going to be difficult to sell, leading many to speculate they might have been destroyed.

Writing for the New Yorker, Jake Halpern speaks with Tomic and in a downright readable profile, attempts to figure out why. Here’s an excerpt:


Many of the luxurious apartments that Tomic broke into had valuable paintings, but he tried to resist taking them, knowing that they would be difficult to unload. “To sell them was dangerous, and I didn’t have reliable sources abroad in order to flog them to collectors or receivers,” he told me. Occasionally, though, the allure of the art proved overwhelming, and Tomic took what he found—including, he says, works by Degas and Signac. “A decent amount passed through my home,” he wrote. He hid some pieces in a cellar, “and some stayed with me for a long time, on the wall, and it’s in these cases that I fell in love.”
This might sound like braggadocio, but Tomic did make off with some masterpieces. In the fall of 2000, in an episode that subsequently made the papers in France, he used a crossbow with ropes and carabiners to sneak into an apartment while its occupants were asleep and stole two Renoirs, a Derain, an Utrillo, a Braque, and various other works—a haul worth more than a million euros.


Jake Halpern, The French Burglar Who Pulled Off His Generation’s Biggest Art Heist, The New Yorker, Jan. 7, 2019, https://www.newyorker.com/magazine/2019/01/14/the-french-burglar-who-pulled-off-his-generations-biggest-art-heist [https://perma.cc/M7FK-M39R].

Its a terrific profile, and if you enjoyed it, it recalls another terrific read, David Grann’s profile of the prolific aging bank robber Forrest Tucker.

Stéphane Breitwieser alleged to have committed more thefts


Sibylle of Cleves at the time of her betrothal to Electoral Prince John Frederick, by Lucas Cranach the Elder, 1526. This work was stolen by Breitwieser in 1995 from a castle in Baden-Baden.

The notorious art thief Stéphane Breitwieser who committed numerous thefts in France, Switzerland, and Germany between 1995 and 2001 is alleged to have continued committing crimes after his release from prison. He worked as a waiter travelling around Europe, and stole on average once every 15 days a quantity of art estimated to total $1.4 Billion. In 2006 he wrote an account of his thefts. But that book has not it seems sold very well, or occupied Breitwieser’s time.

Vincent Noce reports for the Art Newspaper that:

He had been under surveillance since 2016 when he offered a 19th-century paperweight on eBay. Several such objects were stolen from the crystalware museum in Saint Louis, owned by the fashion house Hermès. At his house in the city of Marmoutier, police also discovered roman coins from an archeological museum and other pieces from local and German galleries; €163,000 in cash was stashed in buckets at his mother’s home.


Serial art thief Stéphane Breitwieser arrested—again, The Art Newspaper (Feb. 14, 2019), http://theartnewspaper.com/news/serial-art-thief-stephane-breitwieser-arrested-again [https://perma.cc/NR7T-97LN].

Successful Trial Attorney, Unsuccessful Art Owner

La Plaine de Gennevilliers, by Claude Monet

One of the times when thefts of art are most common is surrounding holidays and festive events. The most obvious example is of course the Isabella Stewart Gardner theft. The same goes for large homes as well. Tony Buzbee, a successful Houston trial attorney found himself the victim of a home burglary early Monday morning. He had apparently had a Superbowl party at his large mansion the evening before, and discovered a man riding away on a moped from his garage at around 6 a.m. on Monday. He discovered that an estimated $21 million worth of goods was stolen, including this art:

  • Pablo Picasso’s ‘Femme Accoudee’ painting, valued at $216,611
  • Claude Monet’s ‘La Plaine de Gennevillers’ painting, valued at $1,273,125 (auctioned at Christies in 2006)
  • A Fernand Leger painting, ‘Paysage au coq rouge’, valued at $1,284,015
  • Pierre Bonnard’s ‘Jeune Femme au Chapeau noir,’ valued at $832,125.00
  • Jean Pierre Cassigneul’s painting, ‘Femme en Vert,’ valued at $111,563
  • Childe Hassam’s ‘California Hills in Spring’ painting, valued at $985,000.

Buzbee has had trouble keeping his art safe before. In 2017, a first date with a Dallas court reporter got out of hand and she allegedly, in a drunken frenzy, started throwing sculpture and damaged a couple of Andy Warhol paintings when Buzbee tried to call her a ride home.

Locally, Buzbee has a reputation as a colorful trial lawyer apart from his art troubles. In 2016 he hosted a fundraiser for Donald Trump, and he’s currently running a Trumpian mayoral campaign. He has netted some fantastically high sums of money in a number of high profile trials, but also gained notoriety for parking a M4A4 Sherman Tank, dating to WWII, in front of his home. That street is River Oaks Boulevard, one of the wealthiest streets in Houston, and probably in all of the United States.

But he continues to have a hard time securing his art.

A recovered de Kooning reveals more questions

“Woman-Ochre” by Willem de Kooning

In 1985 this work of art by Willem de Kooning was stolen from the University of Arizona Museum of art. The thieves entered the museum when it opened, the day after Thanksgiving. One of the thieves, a woman, distracted the museum security guard, while a man went upstairs and cut the canvas from the frame. The work has now been returned, and the story of the theft and recovery is pretty remarkable. The reporting indicates that the work very likely was stolen as a prize for a couple’s private collection, hidden in plain sight behind their bedroom door.

The painting was recently discovered in the estate of Rita Alter after her death. Rita and her husband Jerry may have been the thieves. The Arizona Republic reports:

Jerry and Rita Alter spent Thanksgiving Day 1985 with family in Tucson.

A newly discovered photo from the gathering shows them smiling side by side at the dinner table, plates of pumpkin pie in front of them.

Jerry was a retired music teacher and Rita a speech pathologist; a couple of New Yorkers in their 50s who had moved to rural New Mexico.

A day after the photo was taken, a valuable painting by the artist Willem de Kooning was taken from the University of Arizona Museum of Art in Tucson. Officials believed the thieves — a man and a woman — distracted a guard, cut the painting from the frame, rolled it up and carried it out of the museum under a coat.

The thieves and the painting disappeared without a trace.

Composite sketches, in hindsight, resemble the faces in the Thanksgiving photo, down to their position side by side.

Here’s a terrific local news documentary on the theft, which hints that there may have been other thefts:

Antonia Farzan, A small-town couple left behind a stolen painting worth over $100 million — and a big mystery, Washington Post (Aug. 3, 2018), https://www.washingtonpost.com/news/morning-mix/wp/2018/08/03/a-small-town-couple-left-behind-a-stolen-painting-worth-over-100-million-and-a-big-mystery/.
William K. Rashbaum, A de Kooning, a Theft and an Enduring Mystery, The New York Times, Dec. 905, 2017, https://www.nytimes.com/2017/09/09/nyregion/a-de-kooning-a-theft-and-an-enduring-mystery.html.
Anne Ryman, Who stole the $100M masterpiece? Clues emerge in year since recovery of Willem de Kooning painting, Arizona Republic (Aug. 1, 2018), https://www.azcentral.com/story/news/local/arizona-best-reads/2018/08/01/art-heist-woman-ochre-clues-emerge-willem-de-kooning-painting-recovered/789652002/.
Discovering de Kooning: A WFAA documentary (WFAA dir.), https://www.youtube.com/watch?time_continue=189&v=fwvqHeb32lY.