Stolen Rembrandts, other masterpieces, net thieves little more than heat, say authorities The largest art heist in history, a brazen theft of masterpieces by such painters as Rembrandt, Vermeer and Manet valued at $580 million, likely left the thieves with nothing but heat. In the early morning hours of March 18, 1990, two men disguised as police officers conned their way into Boston's Isabella Stewart Gardner Museum and, after tying up the security guards, made off with 13 artworks -- including Rembrandt's only seascape, "The Storm on the Sea of Galilee," and Vermeer's "The Concert," estimated by itself to be worth more than $200 million. Twenty-two years later, the priceless masterpieces remain missing and authorities say the paintings -- like others stolen in high-profile art heists, including one in the Netherlands last month -- are likely stashed away, of little value to the thieves who risked everything to steal them. Even though these paintings are worth $500 million, really they're worthless because there's no market for it. FBI Special Agent Geoff Kelly "Even though these paintings are worth $500 million, really they're worthless because there's no market for it," FBI Special Agent Geoff Kelly told FoxNews.com. Kelly said it's possible the famous artwork stolen from the Boston museum has changed hands over the years, but said it is "virtually impossible" to negotiate a deal for the highly recognizable art. The problem, he said, is that no one will buy it. You'd never find a buyer for it ...The black market for stolen art is [between] 6 and 8 billion a year. It's a huge market, but it's basically comprised of a lot of little things as opposed to a Vermeer," said Kelly, who has headed the investigation in Boston for the past 10 years. "I don't believe this heist was intended to take these and sell them somewhere," he said. How they went about removing the paintings - slicing them from their frames - that's indicative of a rank amateur when it comes to art theft... That tells us right there it's probably not an experienced art thief... it's probably not a contract theft. Historically, experienced thieves have made off with valuable art so they can later seek a ransom from the owners, the museum or the insurers. The paintings are "ransomed back to their victim museums using the insurance company as an intermediary," Kelly said of other known cases. The museum in the Boston heist, however, did not have insurance 22 years ago -- and still does not -- according to Kelly. Another case of great magnitude occurred in France in May 2010, when a masked man broke into Paris' Musée d'Art Moderne overnight and left with five famous works, including Picasso's "Le Pigeon aux Petits Pois" and Matisse's "La Pastorale." French authorities are reportedly still searching for the suspect, who they believe acted alone, and have said the treasured artworks cannot be sold due to their very fame. And just last month, professional thieves in the Netherlands walked away from the Kunsthal Museum in Rotterdam with priceless works, like Picasso's "Harlequin's Head," Claude Monet's "Waterloo Bridge, London" and "Charing Cross Bridge, London" and Matisse's "Reading Girl in White and Yellow." The works in total are worth hundreds of millions of euros if sold legally at auction -- a deal that would be impossible for thieves because of the highly-publicized nature of the crime. "I think we give thieves too much credit," said Chris Marinello of the London-based Art Loss Register, which helps law enforcement track stolen artwork worldwide. I don't believe that they always think about what they're going to do next after they steal the artwork. "I think they steal it to convert it to cash somehow and they truly don't recognize how difficult it is to sell," he said. Marinello said thieves could try to seek a ransom for the stolen items or attempt to sell them on the criminal market for a small fraction of their real worth. "The art could travel in the underworld at 5 to 10 percent of its true value and be used as a sort of a currency where they will exchange art for drugs or weapons," Marinello told FoxNews.com. He said some thieves also have attempted to use stolen art as a "get-out-of-jail-free card." "If there was ever an instance where the thief was captured, he could go to authorities and say give me a lesser sentence and I will tell you where the paintings are," he said. In that way, art serves as a valuable commodity. Marinello said there are thousands of examples in which authorities nabbed the crooks because they tried to sell the work on the market. A few years ago, he tracked down a stolen Andy Warhol piece after it showed up at auction in New York. The Art Loss Register is the world's largest database of stolen art, with 380,000 items currently listed. Perhaps the most famous example occurred in 1911, when Leonardo da Vinci's Mona Lisa was snatched from the Louvre museum in Paris. Italian officials recovered the masterpiece after the perpetrator, Vincenzo Peruggia, tried to sell it to a local dealer in Florence. Marinello said the idea that a crooked private investor somewhere commissions the art heists is "a Hollywood fantasy." "In all the years I've been doing this, I've never encountered this mysterious individual," he said. What we do encounter are just common thugs. The same people that steal credit cards are the same types of people that steal artwork. "They don't look like Pierce Brosnan," he said. They are just common low-life criminals. Anyone with information regarding the Gardner theft is urged to call the FBI at 617-742-5533. Email this reporter at Cristina.Corbin@FoxNews.com.