Wiretap recordings of President Giorgio Napolitano were destroyed on Monday following orders from Italy's constitutional court -- on the same day he was due to be sworn in for an unprecedented second mandate, Italian media said.
The recordings of conversations between Napolitano and former interior minister Nicola Mancino were made as part of an investigation into alleged secret negotiations between parts of the state apparatus and the mafia in the early 1990s.
The court had in December ordered the conversations destroyed, which were recorded because Mancino's phone was tapped, after a formal complaint by the president who has full immunity.
The wiretap contents have never been disclosed.
Investigators have been probing contacts between the mafia and state officials following a series of mafia attacks and the killing of top judges Giovanni Falcone and Paolo Borsellino.
Prosecutors on the case in Sicily have filed charges against 12 people -- six mafia bosses and six current or former representatives of state institutions including two former ministers.