Mob, and mob hits are one of those things I can go down the rabbit hole one afternoon reading about. If you are interested and have nothing to do for a while start looking at Sicilian or Naples mafia stuff - where the mafia is still very active. It's interesting, in Sicily the mafia is almost justified because the people needed some power to counter the corruptness of their government.
One of the more recent ones was this guy, Giovanni Brusca. Dude killed between 100-200 people, including kidnapping an 11 year old boy and torturing him for 26 months to try and get the boys father to do what he wanted. Finally caugh him because they pinpointed his location by plainclothed officers driving around on loud motorcycles and listening in on phone calls to see when they could hear the motorcycle through the telephone.