From Reuters:

Take a second look at that signed Picasso print you bought on eBay.A ring of art counterfeiters has sold thousands of prints since 1999 bearing the forged signatures of Picasso, Miro, Dali and other famous artists to buyers around the world.

“Thousands of people will learn they … bought a fake,” said Chicago-based U.S. Attorney Patrick Fitzgerald, who announced indictments on Wednesday charging two Americans, a Spaniard from Barcelona, and two Italians from Milan and Monsummano with multiple counts of fraud.

Art theft and smuggling is a $10 billion market.