What a strange story. The worlds most successful art thief did it not for profit or prestige, but apparent mental illness (compulsion). He was only caught because he was spotted, escaped but returned 2 days later to finish the job. He got 3 years, did it again, got another 3 years and still hasn't stopped! Compulsive behavior is the only way this makes sense to me.

Another piece of trivia is that when he was arrested his mother destroyed a lot of the art. She got 3 years for doing that.