[1][2] Although descendants of the old, established rural Mafia, the Greco cousins quickly learned to profit from the post-war economic boom and became involved in cigarette smuggling and heroin trafficking.
Joseph Bonanno, Lucky Luciano, John Bonventre, Frank Garofalo, Santo Sorge and Carmine Galante were among the American mafiosi present, while among the Sicilian side, there were – apart from the Greco cousins – Giuseppe Genco Russo, Angelo La Barbera, Gaetano Badalamenti, Calcedonio Di Pisa and Tommaso Buscetta.
[5][6] According to Buscetta, who became a repentant in 1984, "Ciaschiteddu" Greco was involved in the killing of Enrico Mattei, the controversial president of the state oil company Ente Nazionale Idrocarburi, who died in a mysterious plane crash on October 27, 1962.
[7][9] Gaetano Iannì, another pentito, declared that a special agreement had been achieved between Cosa Nostra and "some foreigners" for the elimination of Mattei which was organized by Giuseppe Di Cristina.
[13] On 30 June 1963, a car bomb exploded near Greco's house in Ciaculli, killing seven police and military officers sent to defuse it after an anonymous phone call.
[14] Meanwhile, in Venezuela Greco formed alliances with the Gambino crime family in New York and the Cuntrera-Caruana Mafia clan from Siculiana (Sicily) to facilitate drug trafficking.
[15] While he resided in Venezuela, "Ciaschiteddu" Greco still remained an important figure in the internal leadership of Cosa Nostra, for which he travelled to Italy regularly.
[16] In January 1978, an ailing Greco travelled from his home in Venezuela to Italy in an effort to restrain Gaetano Badalamenti, Giuseppe Di Cristina and Salvatore Inzerillo from retaliating against the growing power of the Corleonesi headed by Totò Riina.