Artist Pablo Picasso
Art theft has been a practice since the beginning of intellectual property. it takes on many names and has many faces, only one of which is the robbery of physical objects. Art theft also comes in the forms of forgeries, copycats, fraudulent claims of author- or ownership, illegal publications, and confiscation. It is shocking to learn that it is the 4th most prominent economic crime below drugs, arms, and money (the crimes normally associated with criminal cartels, gangs, corrupt governments). Perhaps this comes as news to us because the focus of criminal actions that do direct economic and bodily harm come to the forefront of media reports on the subject. Yet, it would seem, despite art theft's ranking in the criminal world, it is actually a very inefficient way to make vast sums of money. Since many of the world's most highly valued pieces of art are to be found in museums, they are easily recognizable and their theft is well publicized. This makes finding a buyer for the work a difficult and even dangerous task. Even when a buyer can be found, they are often not willing to pay more than a few percent of the real value of the painting because of the nature of the black-market sale. 
Maya with Doll, 1938
In February of 2007, two Picasso oil paintings were stolen. This theft did not take place from a museum, as museums are often well guarded, barred, and installed with complex anti-theft technology. Instead the thieves targeted the granddaughter of Picasso himself who had inherited a number of his works. The Picassos were cut from their frames after the thieves, there are reported to have been 3, broke into the house. Without the sounding of the alarm or the breaking of the front door, Ms. Diana Widmaier Picasso believes that the men must have been professionals with the keys to the house or the code to the alarm system. The loot is reported to have been anywhere between 34 million Euros and 66 million Euros, depending upon the source cited. It is difficult to know the exact value of the works on the market as they have never been sold at auction (the norm for evaluating an artwork's liquidity).
Portrait of Jacqueline, 1961
The two paintings "Maya with Doll" and "Portrait of Jacqueline" were recovered several months later by French police in Paris. The police were said to have received a tip which lead them to follow a group thought to be holding the paintings and awaiting the opportunity for a sale. The group was apprehended on August 7, 2007 with the rolled canvases in tow and three men were arrested for the robbery. The artworks in question were part of a large family collection, but were still well known in the art community and so it is assumed that the paintings were destined for the black market had the police not intervened. An article on the robbery quotes 444 missing Picassos on the London Art Loss Register and cites an active community in the production of Picasso forgeries.
If the thieves had been able to sell the work on the open market, it is no doubt that they would have gained a fortune. Not only because these works were of a special quality but also because they had previously been owned by Picasso's granddaughter, an art historian herself. Yet this would have been an impossibility and the works would most likely have sold for only a fraction of the price on the underground market. Therefore the value of stolen works decreases significantly by economic standards, but the value of recovered pieces increases due to the drama and highlighting of the historical importance of the pieces (done by media coverage). The pieces recovered are then not only valuable art pieces but valuable works ensconced in historic significance and modern mystery. The implications are that the historical and cultural value of the work increases because of the threat that the work could have been lost forever. In fact, one owner of a recovered Picasso decided not to sell the work, even after its worth tripled, because of the increase in foot traffic into his gallery brought on by the display of the piece. The cultural value has increased so much that the symbolic value of the work outweighs any monetary gain to the owner.
http://www.nytimes.com/2007/02/28/news/28iht-pablo.4756042.html
http://www.usatoday.com/news/world/2007-02-28-picasso-stolen_x.htm
http://www.usatoday.com/news/world/2007-08-07-france-picasso_N.htm
http://www.artexpertswebsite.com/pages/artists/picasso-mysteries.php