Italian police said Monday the suspect, Cosimo D'Amato, recovered the explosives from buildings destroyed during World War II, the Italian news agency ANSA reported.
A bombing campaign by the Cosa Nostra killed anti-mafia judges Paolo Borsellino and Giovanni Falcone in separate explosions in 1992. Falcone's wife and three of his bodyguards also were killed.
The explosives allegedly provided by D'Amato are believed to have been used in explosions in Rome in 1993 and 1994 in which no one was hurt.
Cosimo Lo Nigro, a relative of D'Amato's, was among the people convicted in the bombings.