"poltergeist." the most expensive painting ever sold at the center of a legal fight shaking up the art world. leonardo da vinci's portrait of jesus was presumed lost for hundreds of years only to be rediscovered this century. the expert to put the multimillion-dollar price tag speaks exclusively to cnn. shining the light on the murky world of art dealing. >> reporter: billion-dollar lawsuits, claims of subterfuge surrounding the most expensive painting. the bouvier affair as it's dubed the fiercest feud witnessed in the art world, an industry that's developed a rocky reputation for its way of doing business. >> opacity, lack of transparency, greed, tax evasion, money laundering, dishonesty, dissembling,