It takes a certain psychology to exploit art’s loopholes: a tendency toward self-aggrandizement, a loose relationship with the truth, and a sense of superiority, particularly vis-à-vis art royalty. Many forgers take a perverse pleasure in thumbing their noses at gatekeeping elites. And forgers can be something of a Rorschach test for the public. The art world, with its exclusivity, money, and pretension, elicits strong, sometimes negative reactions. The idea of someone skilled enough with a paintbrush or pen to fool the rich and powerful can be tantalizing. “To art critics, the forger is a mediocre artist seeking revenge; to the media, a conman interested only in money; to the apologist, he is the equal of the masters he forged; to the public he is often a folk hero,” Wynne writes.

There are plenty of ways for forgers to exploit opportunities in the way art is produced and authenticated. Although the public celebrates solitary genius—one individual being singularly responsible for an oeuvre—renowned artists over hundreds of years have signed pieces produced by the people they employ in workshops. Andy Warhol called his studio the Factory for that reason. Determining what is genuine, made by a particular hand, is a tricky business, and the unregulated ecosystem of trained experts, historical documentation, and scientific techniques used (or not used) for authentication lets through plenty of fakes.

This collection of talents, such as they are, isn’t as rare as it might seem. Fakes are everywhere in the art world. Thomas Hoving, the former director of the Metropolitan Museum of Art, estimated in his 1996 book, False Impressions: The Hunt for Big-Time Art Fakes , that 40 percent of the 50,000-odd works he examined during his tenure at the museum were “either phonies or hypocritically restored,” an idiosyncratic way of saying that someone had added signatures or flourishes to a real piece. Other estimates of how much of the art market is fake range from 20 percent to more than 50. As Wynne points out in his book, this is not a recent phenomenon: In 1940, Newsweek quipped that “of the 2,500 authentic works painted by Jean-Baptiste Camille Corot, 7,800 are in American collections alone.” Some experts believe that museums have the greatest number of forged works, in comparison with galleries and auction houses. Once it’s been acquired, art in museums isn’t likely to be subjected to further scrutiny.

“For as long as mankind has coveted objects for their history, their beauty, their proximity to genius, the forger has been there with a mocking smirk ready to satisfy the demand,” writes Frank Wynne in his book I Was Vermeer, a study of Han Van Meegeren, a notorious art forger who swindled, among others, Hermann Göring. A successful forger has the ability to produce art of high quality, certainly, and also an inside knowledge of the workings of the art world, from its business dealings to its social mores. A forger is a storyteller, even a performer—someone who can charm customers, appear trustworthy, and spin a convincing tale about where an artwork came from and how they came to possess it. To forge art takes showmanship and a healthy dose of chutzpah. Frauds must be willing to brazenly claim that a work is genuine; some go so far as to approach experts or artists themselves and request authentication.

The pair were cleared, and news of their discovery headlined the evening news in Romania. The story quickly spread around the world, picked up by outlets like The Guardian , the Associated Press, and Le Figaro . A sensational crime, an anonymous tip, and a prized work of art buried in the earth made for a remarkable tale. Reporters and art lovers alike were hopeful that authentication efforts would prove that a masterpiece had indeed been found.

Five days later, Feticu and Westerman were tromping through a snowy forest in eastern Romania, near the village of Carcaliu, where the thieves were originally from. Following the letter’s instructions, the writers walked until they located a stripe of red paint on a tree. After clearing away snow, leaves, and a thin layer of dirt at the foot of the trunk, Feticu and Westerman found a rock. Underneath, wrapped in plastic, was the treasure they’d hoped would be there. The black ink, the pastel shading, the elongated, contorted face with a bulbous nose, close-set eyes, and deep wrinkles that hardly look like laugh lines—it was the missing harlequin.

The letter wasn’t a suicide note—it was a treasure map. The harlequin was Pablo Picasso’s Tête d’Arlequin (Harlequin Head). Completed in 1971, two years before the artist’s death, it’s a drawing in ink, colored pencil, and pastel on thick brown paper. The work was part of a private collection that hung in Rotterdam’s Kunsthal museum, a pavilion designed by Rem Koolhaas, until the early morning hours of October 16, 2012, when thieves broke in through a back door and made off with the Picasso and six other works, by Henri Matisse, Claude Monet, Paul Gauguin, Lucian Freud, and Jacob Meyer de Haan. Experts estimated that the missing items were worth as much as $115 million. Four Romanian men were apprehended, tried, and convicted, but the art was never recovered. The mother of one of the men claimed to have burned it in her kitchen to protect her son; she later retracted her statement, but a forensic analysis of the ash in her stove found traces of what appeared to be nails from art frames used before the end of the 19th century. Some experts believe that at least three paintings went up in flames.

At first the letter read to Mira Feticu like a suicide note. “I am tired of being the guard,” it said. “The story is over. It only brings trouble.”

II.

One day in late September 1993, Sue Cubitt, an art historian, was sitting at her desk at Karl and Faber in downtown Munich. The 70-year-old auction house held art sales twice a year, and the catalog for the fall auction was nearly due at the printer. Cubitt was going over details of the works that would be on offer when a Dutch dealer came in without an appointment. “He was more like a kind of bureaucrat. He was a sort of unobtrusive character who spoke quite softly,” Cubitt recalled. “He raised no suspicion.”

The man introduced himself as Jan Van den Bergen, and he offered a drawing by Karel Appel for sale. Appel, also Dutch, painted expressive, figurative abstractions, often in bright colors, and he drew inspiration from folk and children’s artwork. Associated with the COBRA group—an acronym for a loose association of artists in Copenhagen, Brussels, and Amsterdam—Appel was prolific and well-known in the European art scene. That day in 1993, Van den Bergen handed over an Appel drawing created with a brush and pen, in India ink and crayon. Dated 1950, it depicted several crudely drawn figures and was titled Deux Enfants et un Poney (Two Children and a Pony).

While many consigners haggle over a minimum price at which to sell their pieces at auction, Van den Bergen said that he wasn’t picky. Cubitt took the drawing and jotted down some notes so that she could draw up a contract. Van den Bergen gave her an Orléans, France, address for his gallery. Back then, throughout the art world, it wasn’t customary to ask for personal identification—this was a gentleman’s business, and no one wanted to be rude. Unbeknownst to Cubitt, Van den Bergen made other stops around the same time to consign works at auction houses in Bonn, Cologne, Hamburg, and Dusseldorf.

Van den Bergen promised to follow up promptly with the Appel drawing’s certificate of authenticity, which he had neglected to bring with him. Some weeks later, the certificate arrived by mail. It had what Cubitt described as “a very flamboyant Appel signature”—quite large, but with the telltale slanting letters that the artist used. With its authenticity attested to, Karl and Faber decided to put the drawing in its upcoming auction.

Two months later, Cubitt received a fax from Jan Nieuwenhuizen Segaar, the proprietor of Nova Spectra, a gallery in The Hague that represented Appel. Karl and Faber’s auction catalog had come to Nieuwenhuizen Segaar’s attention, and he knew immediately that Deux Enfants et un Poney was not an original work. Concerned, Cubitt informed her boss. In her telling, he wasn’t convinced that he should pull the work from the auction—it already had bids, and Cubitt said he “was keen on every single deal that he could make.” She remembered telling him that they had no choice, not with “negative information” in hand. “I won, and it did not come under the hammer” of the auctioneer, Cubitt told me.

The fact that Van den Bergen had consigned an inauthentic work didn’t immediately raise eyebrows. Mistakes happen; people don’t always know when they’re handling a forgery. A dealer might be asked by a client to sell an inherited work that turns out to be a fake, or one dealer might mistakenly sell a forgery to another. When a work is considered suspect, an auction house calls an expert—the artist, their primary dealer, a conservator—for verification. In most cases, if the work can’t be authenticated, the house simply declines the sale, explains why, and returns the work to the consigner. “You don’t just run to the police and say, ‘I think something’s wrong, can you deal with it?’” Cubitt explained.

The episode with Van den Bergen might have been forgotten, but six months later, on March 30, 1994, he returned to Karl and Faber. Again it was just days before the house’s auction catalog was due at the printer. Van den Bergen had three items he wished to consign: an ink drawing by Marc Chagall, a gouache by Asger Jorn, and a painting by Appel. Cubitt was on holiday, so her secretary received the items and drew up the necessary paperwork. The contract stipulated a total value of 80,000 deutsch marks (about $50,000 at the time). The auction that would include the works was scheduled for early June.

When Cubitt returned to the office, she found the items waiting for her. “I remember looking at the name of the consigner and thinking, Aha, we have to be very careful here,” Cubitt recalled. She leaned the three works against a wall, facing outward so that she could see them each time she walked past. “I’d come back to them and look at them again and again,” she said.

None of the works was anything special or unusual—the Appel was a bit garish, while the Chagall, in Cubitt’s words, was “decorative, a lot of blue, one of these typical floral bouquets.” But the certificate for the Chagall made her suspicious. It didn’t have several of the usual pieces of information. It lacked a number—akin to that included on an invoice—that would indicate its assigned place in the authentication records of the Comité Chagall, a foundation in Paris that verifies the artist’s work. It bore the foundation’s official stamp but neither an address nor a date of review. Instead, there was a typewritten paragraph attesting to the work’s authenticity.

Then Cubitt noticed a typo. The certificate said that the Chagall had been made “environs 1952.” In French, environs means “in the area of”—whereas environ means “circa.” It isn’t a mistake a fluent French speaker is likely to make. “That’s what really set the alarm bells going off,” Cubitt said.

She consulted experts about all three of Van den Bergen’s latest consignments, reaching out to Nieuwenhuizen Segaar at Nova Spectra to review the Appel, an art historian named Otto Van de Loo to look at the Jorn, and the Comité Chagall in Paris. All of them rejected the works as inauthentic. The Comité said that the certificate for the ink bouquet was a fake, but a good one. Nieuwenhuizen Segaar told The Art Newspaper that the certificate on the Appel was also suspect. “Appel rarely issued certificates,” he said. “When he did, he didn’t sign them like this, nor did he go into details about the technique used.”

Cubitt decided to call the police.

She contacted Ernst Schoeller, the superintendent of the art and antiquities division of the State Office of Criminal Investigations in Stuttgart. A trim man with arched black eyebrows, Schoeller specialized in art crimes, including forgery cases. In response to Cubitt’s tip, Schoeller called several auction houses across Germany. He learned that Van den Bergen had recently offered 35 works to five institutions. The items were of comparatively modest value. The highest reserve price—a minimum amount below which an auction house agrees not to sell—of any of the works was around 37,500 deutsch marks ($22,500) for a Chagall. Still, a fraudulent operation on the scale of dozens of consigned works was notable.

Schoeller’s interest was piqued. By chance, due to other investigations, he’d gone to Paris a few months prior, where he’d procured one of the Comité Chagall’s authentication stamps. Schoeller was quickly able to confirm that the stamp used on the Chagalls that Van den Bergen had consigned was fake—it was the wrong size. Suspecting that he had a seasoned fraud on his hands, Schoeller advised German auction houses not to give Van den Bergen notice that he was being investigated, lest he go dark.

Schoeller traveled to France, where along with local police he arrived at the address that Van den Bergen had given to Cubitt as the location of his gallery. It was on the Rue Maltotiers in Orléans. Except there was no gallery: It was just an apartment building. A visit to an address that Van den Bergen had used in Paris led investigators to a plumbing and bathroom-fixture shop. A woman who worked there said she would occasionally forward Van den Bergen’s mail to yet another address in Orléans, so the police returned there. To Schoeller’s consternation, that address was a front, too—it was the site of an abandoned house. But the tip wasn’t for naught: The post box was the same one listed as a return address on some of Van den Bergen’s fakes when they were delivered to auction houses. It was also where Schoeller found a check from a German auction house for 10,000 deutsch marks (around $6,100).

In a matter of days, their pursuit took Schoeller and the French authorities farther south. In the early morning of May 6, 1994, Schoeller and a phalanx of police arrived in Linazay, a town of only about 200 residents situated between the cities of Poitiers and Bordeaux. At the end of a long driveway of flowering chestnut trees was a twin-turreted, 20-room mansion called Château de la Chaux. (Chaux means “lime,” as in whitewash.) Van den Bergen rented the property for about 5,000 francs ($900) per month.

No one was home. A gaggle of geese cackled in the expansive interior courtyard, threatening to give away the plainclothes police officers who planned to hide among the trees and bushes, waiting for Van den Bergen’s return. The person who eventually arrived was a woman named Ellen Van Baren; she was Van den Bergen’s girlfriend. She drove onto the property in a battered Renault and quickly found herself surrounded. Later, in a TV interview, she recounted seeing between eight and ten police cars, and “one German guy [who] was very excited and asked me all kinds of questions. He walked around the house, and the more rooms we entered, the more paintings we saw, the more excited he got.”

Inside the château, Schoeller found hundreds of artworks that he and the French police suspected were fraudulent. They were attributed to masters like Picasso, Matisse, and Joan Miró. They were arranged in neat stacks, apparently ready for sale. Fake Chagall paintings hung above the stove, drying. Several rooms were designated for a particular artist whose style was being faked. Authorities also found half-finished works, sketches for new ones, contracts with auction houses in Belgium, Switzerland, and New York, and false authentication certificates. Moreover, Van den Bergen had all the tools required to produce fake certificates of authenticity, including a bag full of stamps and 30 vintage typewriters used to approximate typefaces from various time periods. In a dustbin were strips of paper cut from forged certificates to eliminate watermarks, which might have given away the documentation’s true age.

“You know you’ve reached the end of your hunt,” Schoeller said years later in a TV interview. “You’re at the source of the whole evil.” He called the feeling of discovering what was inside the château “sublime.” (Schoeller, now retired, initially seemed willing to discuss the case but ultimately declined to be interviewed for this story; he said that he didn’t want to spend his retirement talking about his work.)

The Telegraaf, a Dutch newspaper, called the cache the largest quantity of fakes ever found in a single location. Schoeller’s investigation estimated that the total value, had the works been sold under false pretenses, was likely more than five million deutsch marks ($3.1 million). Given the scale of production on display, it was difficult to estimate just how many fakes had already entered the market, purchased by unsuspecting buyers before the police caught on. Newspapers reported that forgeries produced at the château had turned up in Switzerland, France, Belgium, Holland, Luxembourg, Scandinavia, and the United States.

Scale wasn’t the only issue that made tracking sales difficult. “The works are so damn good,” Schoeller told the Stuttgarter Nachrichten, “that the forgeries are hard to recognize.”

Creating a damn good fake isn’t easy. Beyond a superlative ability to paint, a forger needs materials appropriate to the era in which the real artist worked—canvases, frames, and paint pigments. These can be difficult to source or re-create, and many forgers are found out because of mistakes they made in their choice of supplies. For example, the presence of acrylic paints, which became available in the first half of the 20th century, would readily give away a fake rendition of an old master’s work. Then there’s the process of re-creating the natural aging that artworks undergo, especially oil paintings and works on paper. Temperature, humidity, dust, and dirt all take their toll. Forgers must “damage” a counterfeit to the extent commensurate with its purported age. Experts armed with UV lights, X-rays, and other technology might see right through the lie.

That is, if such intense scrutiny is applied at all. The technology and expertise required for authentication are expensive. While major museums and high-end dealers have the funds to put acquisitions under a magnifying glass, more modest outfits often do not. They rely instead on the trained eyes of employees, the reputations of consigners, and historical documentation of ownership and certification, known in the art world as provenance. Some of the biggest art cons in recent decades relied on compelling backstories. Wolfgang Beltracchi, who along with his wife, Helene, was convicted of selling some $45 million in forged artwork in 2011, concocted an elaborate tale in which Helene inherited a significant collection from her grandfather. The works didn’t have certification, she claimed, because many of them had been looted by the Nazis, and the paperwork was lost in the process. The Beltracchis went so far as to concoct vintage photographs of Helene posing as her grandmother in front of some of the forgeries, which they presented to auction houses and dealers as proof.

Strategy, or deciding what kind of art to fake, is also key. Potentially blockbuster works—oil paintings by Michelangelo, say, that might be worth tens of millions of dollars—are likely to be put through the authentication wringer. Less prized items are not. Prints, works on paper, and gouaches (opaque watercolors) usually sell for less than $10,000 and pass through small auction houses and dealers. It’s much easier to elude detection when the stakes, relatively speaking, are low.

That may have been one reason Van den Bergen forged the types of works he did—smaller-scale compositions on paper rather than oil paintings. But he may have had other, more personal motives. Among the paintings recovered from the château were large-format abstract canvases, filled with geometric shapes in shades of lime green and orange. They were originals of the artist, and Schoeller wasn’t impressed. “He’s a perfect craftsman but not an artist,” the investigator told the Stuttgarter Nachrichten. “He has no style of his own.” Perhaps that’s why he’d become a forger in the first place—an abundance of artistic ambition without the vision to realize it.

One way or another, authorities hoped to get answers from him: Van den Bergen was apprehended at a train station, slightly tipsy, a few hours after the raid at the château. He joined Van Baren in the Orléans jail. As Schoeller and other investigators would learn, it wasn’t the first time that the forger had been detained. And his name wasn’t Jan Van den Bergen—it was Geert Jan Jansen.