I don't know if it's a gangster/mobster/criminal or anything (I doubt it), but I just found out that the "Keyser Soze" character from the movie 'The Usual Suspects' (1995, Bryan Singer, my all time favorite) was loosely based on a guy named John List who killed his wife and children and then dissapeared for 17 years!!

now there's already a movie about a guy like that, The Usual Suspects (duh) but another adaptation would be exciting.....