Mr van Rijn says that when they left, they also left their art.

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By the mid 1990s, Mr van Rijn claims to have stolen a hoard of Nazi platinum from Libyan leader Colonel Gaddafi.

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But Mr van Rijn said that it was not just Italy's auction houses who were behind the "non-stop supply of Old Masters" leaving Italy.

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The theft took place on the final day of an exhibition entitled "Unknown Treasures, " which had featured prints and etchings by Albrecht Duerer and Rembrandt van Rijn.

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Mr van Rijn, 55, is the rogue Dutch art dealer who helped police set up an arts sting last week which recovered an ancient Peruvian head dress stolen nearly 20 years ago.

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Prospects he identified led to a gas field in West Lake Arthur in southern Louisiana, good for 56 billion cubic meters, and to the Rijn and Horizon fields off the coast of the Netherlands, with 60 million barrels of oil.

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Rembrandt Harmenszoon van Rijn, who died in 1669 aged 63, is widely regarded as one of the most prolific self portraitists, thought to have painted 40-50 pictures of himself in oils and used himself as a model in 32 etchings and seven drawings.

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