Accursio Di Leo

Enrico Mattei helped change Italy's future, first as freedom-fighter against the Nazis, then as an investor in methane gas through a public company, A.G.I.P., and ultimately as the head of ENI, a state body formed for the development of oil resources. October 27, 1962, he died when his private airplane crashed, one minute before it should land at Milan airport. Officially, he died of a flight accident... (imdb)

Film in a docu-film style, it's an act of denounce against the tie between Cosa Nostra and teh sicilian mafia that overlay also the political level. The title come from the tradition to put a stone into the mouth to those killed because they have talked, challenging the veil of secrecy that surrounds the organized crime.