Bosses killed in prison

Vito Cascio Ferro 1943 (the men who ordered to kill Petrosino died in an italian prison because was left by the guards in his cell due the allies bombing)
Angelo La Barbera 1975(first mafia war boss killed with a knife)
Domenico Tripodo 1976(killed in poggioreale as favor that cutolo made to the Distefano ndrina)
Vincenzo Puccio 1989 ( He was killed on May 11, 1989 while detained at the Ucciardone prison:  the killer Giuseppe Marchese smashed his head with a shot of cast iron skillet. To order the murder was the Sicilian boss Toto Riina because Puccio was being organized with some picciotti to take absolute power of Cosa Nostra that was in the hands of Riina)