When Corvez spoke in the courtroom, he chose his words carefully. “I did not ask him to steal,” he said. “I told him, ‘If you happen to stumble across a Fernand Léger, I know someone who would be willing to buy it.’ ” When Corvez was pressed to identify the buyer, he demurred. “It could threaten my safety,” he said.

Birn’s lawyer said that his client was manipulated into the scheme by Corvez. When Birn took the stand, he recalled his decision to destroy the art: “I am paranoid, and this paranoia is reaching its peak. I lose all discernment and I decide to get rid of the paintings. . . . I do not know why I do this. I thought I was being followed by the police. I was convinced that I was being filmed or spied on. I thought to myself that I could not leave the building with the paintings, and so I committed the irredeemable.” Shaking with sobs, Birn repeated three times, “I put them in the trash! ”

Many people suspected that Birn’s story was a ruse. He would not have been the first person to invent such a lie. After a Romanian named Radu Dogaru was arrested for helping to steal seven paintings from the Kunsthal, in Rotterdam, in 2012, his mother claimed to have burned them in her stove. Dogaru subsequently disavowed his mother’s claim, saying, “The paintings were certainly not destroyed. I don’t know where they are, but I believe they have been sold.”

Even Birn’s wife, a fashion executive, doubted whether he had thrown the paintings into the trash. Corvez shared her view, testifying that Birn was simply “too smart” to have done this. Trubuilt, the prosecutor, said of Birn, Corvez, and Tomic, “They know very well that the day they get out of prison the paintings will not have lost value and they will be able to resell them.”

The judge found all three men guilty. Corvez was given seven years, Birn six. As Birn was being taken off to jail, he was hysterical—and yet, Durand-Souffland observed, “Birn didn’t forget to give his car keys to his lawyer.” (Birn did not respond to my requests for an interview. Corvez wrote to me, “I am not opposed to the idea of ​​an interview on this subject, nevertheless, I would like to know what would be my interest in this eventuality—would I be paid, and how much?” When I said that I couldn’t offer money, he stopped communicating with me.)

Tomic, who was sentenced to eight years, was far more collected as he left the courtroom. Many observers felt certain that he knew exactly where the paintings were. Franck Johannès, of Le Monde, told me, “Legally, nothing can be done, even if Tomic knows the truth. It is up to the prosecution to prove that he lied. In France, one has the right to lie at one’s trial. There is no offense of perjury.”

Tomic may be a skilled climber and thief, but the MAM heist required him only to crawl through a ground-floor window and then navigate around the few motion detectors that were actually working. Nevertheless, in the press Tomic’s robbery became known as “the heist of the century.” Charles Hill, the former Scotland Yard detective, is irritated by descriptions of Tomic’s heist as “spectacular” and “perfect.” He told me, “Stealing an art work is actually a rather easy thing to do. In the National Gallery in Washington, the Smithsonian has armed guards, but elsewhere it’s mostly just a few older people staring at a wall.”

Even if Tomic doesn’t quite deserve his aura of glamour, his notoriety will likely only add to the art’s value, if and when it is ever returned. In 1911, a relatively uncelebrated painting by Leonardo da Vinci, the “Mona Lisa,” was stolen from the Louvre. It took twenty-eight hours before anyone even noticed that it was gone. The painting was missing for two years and, during that time, a great many people went looking for it, and the media attention helped turn the “Mona Lisa” into the most famous painting in the world.

I wondered if Tomic might rightly claim credit for a similar alchemy, should the MAM paintings resurface. Aline Le Visage, a consultant who specializes in stolen art, told me that this was unlikely. “The theft at the Louvre in 1911, one of the most beautiful museums in the world, was like an earthquake,” she said. The investigation was aggressive and, for a while, implicated well-known people. The police arrested—and then released—the poet Guillaume Apollinaire; Pablo Picasso was also interrogated. The story stayed in the papers until the actual culprit, an Italian thief named Vincenzo Peruggia, was finally arrested. Nowadays, Le Visage said, robberies of great museums have become commonplace, and the news cycle is blindingly fast—too fast, it seems, for any single image, even one as beautiful as Matisse’s “Pastoral,” to become an enduring icon.

Tomic is imprisoned at the Centre de Détention de Val-de-Reuil, northwest of Paris. One of his regular visitors is his girlfriend, Korine Opiola, a feng-shui consultant. During the police investigation, officers referred to the sex worker who let Tomic sleep over as his “partner,” but this was incorrect. His feeling for her appears to have been more pity than love. (“All I know is that she is a very kind person who does not deserve what she does,” he wrote to me.) His relationship with Opiola is more serious. Tomic, who was released on bail after his arrest, met Opiola in Paris in the months before his trial, at a bar across the street from l’Église de la Madeleine. She was reading a magazine about U.F.O.s, and he asked her if he could have a look at it. “He was not someone who was entertaining me just to pick me up,” she recalled. “You felt like he was really present. I felt his authenticity.” Later, they communicated on Facebook and spoke on the phone. Opiola had no idea that Tomic was about to go on trial for the greatest art heist in a generation.

After his conviction, she began writing to him, and later began visiting him in prison. In his letters to her, she told me, he often laments the fact that his parents brought him back from Bosnia. Opiola told me, “Each time, he writes, ‘They stole my life from me. I would have been a good person. I was obliged to be a thief.’ ”

Opiola believes that Tomic’s current predicament is the result not just of his neglectful parents but also of his fateful visit to the Musée de l’Orangerie. “Vjeran, when he loves a work, he wants to possess it,” she said. I asked her why he couldn’t simply enjoy looking at beautiful paintings. “He does not have that distance,” she said. “It’s an uncontrollable impulse. He wants, he takes.”

Tomic expressed few regrets to me, though he occasionally made hints about the fate of the stolen paintings. In one letter, he wrote, cryptically, that “there is no better place for such art works than where I took them.” He never gave me a sense of where this secret place was, or why it was such an ideal home. In his furtive visits to wealthy apartments, he told me, he had seen many lovely paintings that he hadn’t taken, “because I don’t have the apartment or the manor of those rich people who allow themselves to have private collections.” He went on, “If I had this privilege, I would have acquired a museum by today—I can assure you that.”

In one of our final exchanges, I asked Tomic again if the paintings had been destroyed. No, he replied, adding, “Birn loves the paintings more than anything, and he would have protected them somewhere.” Then, as if unable to help himself, Tomic noted, “One day or another, he will be forced to give them to the person to whom they belong—that is to say, to me.”

In the meantime, Tomic spends his days writing letters and trying his hand as an illustrator. He draws images of ceramics, and hopes one day to sculpt the designs in a studio in Paris that Opiola owns. His black-and-white drawings, which are starkly beautiful, depict oval-shaped sugar pots and goblet-like teacups. The images are accompanied by notations with precise measurements (“3 cm long, 1.5 cm wide”), specific colors (“Red Brick”), and personal observations (“It will be more beautiful without any drawn pattern”). He knows that he is not the next Renoir, but he is gratified to be finally making art. “I do little sketch drawings,” he wrote to me. “I don’t imagine becoming a great master.” ♦