The Isabella Stewart Gardner Museum has sweetened the pie, doubling the reward for the return of the artworks. However, there are some catches … the works must be in acceptable condition (guess they do not want a box full of ashes) and you must collect the reward by December 31. The stolen items have been missing since 1990 so I doubt that doubling the reward will do much good, but it never hurts to try. Good luck!
Source: Will a $10m reward solve the world’s biggest art heist? – CNN.com