Salvatore Riina

a.k.a. "The Beast"(La Belva) due to his violent nature and "The Short One"(U curtu) due to his diminutive height, A member of the Sicilian Mafia who became the most powerful member of the criminal organisation in the early 1980s. Although apparently they never called him these nicknames to his face. During his life-long career in crime he is believed to have personally killed around forty people and to have ordered the deaths of several hundreds more.

During the 1980s and early 1990s, Riina and his Mafia faction, the Corleonesi, waged a ruthless campaign of violence against both rival mobsters and the state which culminated in the assassination of the anti-Mafia prosecutors Giovanni Falcone and Paolo Borsellino. This caused widespread public revulsion against the Mafia and led to a major crackdown by the authorities, resulting in the capture and imprisonment of Riina and many of his associates.

Resource:
http://en.wikipedia.org/wiki/Salvatore_Riina