( CNN ) -- Steven Spielberg led the FBI straight to a stolen $ 700,000 Norman Rockwell painting someone snatched from a Missouri gallery . It was in his collection in California . The original of this Norman Rockwell reproduction was found in the collection of Steven Spielberg last year . Spielberg was n't the thief , and he does n't know who took Rockwell 's `` Russian Schoolroom '' -- an oil of 16 pupils looking at a bust of Lenin . All the A-list director knows is he paid about $ 200,000 for the 16 x 37 canvas in a legitimate purchase . The FBI says its just one example of how pilfered art lands in respectable places . And it was an uncommon ending for stolen art -- someone found it . Recovering masterpieces happens in less than 5 percent of cases , said Bonnie Magness-Gardiner , the FBI 's Art Theft Program manager . Usually , expensive pieces go missing . No one knows who took them . No one gets prosecuted , and everyone wonders , `` Why steal something you ca n't turn to cash quickly ? '' Art thieves do a simple risk versus reward evaluation , said Corine Wegener , associate curator of the Minneapolis Institute of Arts . Thieves know that `` even if they receive only a fraction of the work 's market value , the cash gained was at low risk of death or injury -- museums can be a relatively soft target , '' said Wegener , who 's teaching a University of Minnesota class this month on art theft . But it could be years -- or never -- before the thief sees even a small payoff . In 1990 , robbers took $ 300 million worth of certified masterpieces -- among them Rembrandt 's `` Storm on the Sea of Galilee '' and Vermeer 's `` The Concert '' -- from the Isabella Stewart Gardner Museum in Boston , Massachusetts . No one 's seen them since . On Sunday , robbers made off with one of the biggest art hauls in European history , grabbing four paintings worth an estimated $ 163 million from the E.G . Buehrle Collection in Zurich , Switzerland . They took works by Paul Cezanne , Edgar Degas , Claude Monet and Vincent van Gogh . See what robbers grabbed in Switzerland » . `` These paintings are extremely valuable on the open market , but they 'll never go onto the open market . So at the same time they 're both priceless and worthless , '' said Charles Hill , the former chief of Scotland Yard 's art and antiques unit . `` Some thieves may buy into the myth that a wealthy but unscrupulous collector will contact them and offer to take the art off their hands , '' Wegener said . `` When this does n't happen , the thieves often try to ransom the art back to the museum or the insurance company . '' One London art dealer , who said he has handled stolen works , told CNN on condition of anonymity that an insurance company would rather get art back at a fraction of its original price than pay the owner its insured value . Watch how art thieves operate » . Ransoming art to an insurance company through an intermediary adds `` up to 10 percent of the market value , which ... given the art market , is quite a lot of money , '' the dealer said . David Vuillaume , secretary general of the Swiss Museums Association , told Time magazine that ransom may be what the thieves behind the Swiss heist want . `` We are thinking that maybe in a week or two there will be a ransom demand . But we just have to wait and see , '' Time quoted him as saying . The museum has offered $ 90,000 reward for information leading to their recovery , Time reported . Options for art thieves . Julian Radcliffe , chairman of the Art Loss Register , which operates a database to help recover lost and stolen art , said ransom or reward are unlikely to bring results . `` It is very seldom that people have been able to undertake a ransom , '' he said . `` This gang might think that a reward has been offered , and that they 'll get the reward . '' But in fact , `` the reward wo n't be paid unless someone is arrested , or there is proper criminal intelligence , '' and that 's unlikely to happen , Radcliffe said . He said the thieves may just be patient , willing to get their payoff decades later . Or the art may move through an underground network , gradually increasing in value , before being slipped back onto the legitimate market . Take Spielberg . He bought `` Schoolroom '' in an above-the-board transaction . `` Usually , these pictures will change hands in the criminal underworld at a fraction -- 1 percent or less -- of their true market value , '' Radcliffe said , before someone tries to get them back into the international market . In such an effort , the seller may hope the work has been forgotten over time or they may disguise it as a copy or student re-creation . `` They may try and sell them not as being by Degas , but as being a copy , or school , or by a follower of one of the great artists . And that is the ways in which they try and get them on the market , '' Radcliffe said . The original thieves rarely face justice , the FBI 's Magness-Gardiner said . `` The stolen items turn up years , sometimes decades , after the theft , '' she said . `` Because a work of art does not require a title document in order to be transferred from one owner to another , a stolen object easily enters the legitimate stream of commerce . `` It is impossible to trace them back to the original thief in most cases . Even if the original thief can be identified , there is also a statute of limitations on prosecution for theft , '' Magness-Gardiner said . What happens to stolen art ? Even if the art is recovered , original owners may not get it back . While museum pieces are likely to go back to their collections , private owners may not be so lucky . `` Russian Schoolroom '' remains in Spielberg 's possession while courts determine the rightful owner , a spokesman for the director said . But art stolen from a Los Angeles mansion and sold in Sweden remains with its Swedish purchasers , according to a case file posted on the Web site of the Los Angeles Police Department 's Art Theft Detail . Even though the thief was caught , `` the Swedish government refused to return the paintings , claiming that according to Swedish law , the auction buyers had purchased the paintings in good faith , '' according to the Web site . In the case of Rockwell 's `` Russian Schoolroom , '' someone took it from a gallery in Clayton , Missouri , a St. Louis suburb , in 1973 , according to an FBI synopsis of the case . In 2004 , The FBI 's Art Crime Team found out that the piece had been for sale at a New York Rockwell exhibition 15 years earlier and posted a picture and description of the painting on its art recovery Web site . Spielberg 's staff learned of the search and told the FBI that Spielberg had it in his collection in Los Angeles . He had purchased it from a legitimate dealer in 1989 , an FBI press release said . The agency also determined the painting was auctioned in New Orleans in 1988 , but it has yet to determine who took the painting or its whereabouts from 1973 to 1988 . Whoever took `` Russian Schoolroom '' from the suburban St. Louis gallery in 1973 , or the masterpieces from the Boston museum 1980 , or the works lifted in Zurich this week , should n't be mistaken for a high-society , tuxedo-wearing , `` Thomas Crown Affair '' kind of thief , Radcliffe said . `` These people are the worst sort of criminal . They are just like the criminals who traffic individuals or sell children , or murder . `` They are thoroughly unpleasant people . There is no romanticism in anyway that should be connected to it . '' E-mail to a friend . CNN 's Paula Hancocks and Teresa Martini contributed to this report .
Valuable art can be hidden for decades . Soft targets like museums entice thieves , experts say . Norman was found in Steven Rosen 's collection decades after theft . Nothing glamorous about art thieves , he said .