By Steve Scherer
ROME (Reuters) - Italy's President Giorgio Napolitano testified for more than three hours on Tuesday in an unprecedented appearance in a major trial that accuses the state of holding secret talks with the Sicilian Mafia in the 1990s.
Palermo prosecutors seeking to shed light on a murky period when the mob targeted the state with assassinations and bombings questioned a sitting head of state in a mafia trial for the first time in the country's history.
Among the defendants are Nicola Mancino, who was interior minister at the time and is charged with giving false testimony, and Salvatore Riina, once Italy's most powerful mafia boss.
Riina and eight others in the dock face charges of trying to blackmail the state. All deny any wrongdoing.
The 89-year-old Napolitano is not accused of any crime. He was called as a witness who may have knowledge useful to the trial, but the hearing may tarnish the image of a president who has guided Italy in a period of political and economic turmoil.
Napolitano responded to questions with the "maximum amount of transparency and serenity" and without invoking his constitutional right to remain silent, a statement from the president's office said afterward.
"He said he had been a spectator to the events (of 1992-93), nothing more," Luca Cianferoni, lawyer for the Corleone-born mob boss Riina, told reporters outside the president's Quirinale Palace where the closed-door hearing took place.
Prosecutors allege senior politicians and police, hoping to stem mounting violence, held talks with mob bosses after anti-mafia magistrate Giovanni Falcone, his wife and three bodyguards were killed by a mafia bomb planted under a road in 1992.
The state's willingness to enter into talks after Falcone's murder actually encouraged further bombings, the prosecutors say, including the one that killed another anti-mafia magistrate, Paolo Borsellino, two months later.
At the time of the bombings, Napolitano was president of Italy's Chamber of Deputies, the lower house of parliament. He became Italy's president in 2006.
Prosecutors asked the head of state about a 2012 letter to him from his legal adviser Loris D'Ambrosio that referred to "unspeakable agreements" and implied that Napolitano had known about the talks.
"The president never spoke explicitly of a negotiation" between the state and mafia, and he called talk about any unspeakable agreements "conjecture without any objective elements of proof," said Nicoletta Piergentili, a defense lawyer.
BEHIND CLOSED DOORS
The media were not allowed to cover the proceedings, sparking protests from Italian journalists. Those present at the closed-door hearing were not allowed to record it.
In his statement after the hearing, Napolitano urged rapid transcription of the testimony so it could be made public, a step in line with his active role as head of state.
Unlike other mostly representative presidents, Napolitano has taken critical political decisions such as naming Mario Monti to replace Silvio Berlusconi as prime minister in the 2011 euro zone debt crisis.
About 40 people - including prosecutors, judges and defense lawyers - attended the hearing in a large hall in the 16th century Quirinale Palace in central Rome.
Riina's lawyer Cianferoni also put questions to the president. Riina is serving life in prison for ordering multiple homicides, including those of Falcone and Borsellino.
"As a defense lawyer I come out of this hearing with some cards to play," Cianferoni said afterward, without elaborating.
Napolitano has previously provided written testimony but declined to speak before the court when prosecutors made an initial request in October of last year. He agreed to the hearing last month after a court ruled his testimony would be "neither superfluous nor irrelevant".
(Additional reporting by Roberto Landucci in Rome and Wladimir Pantaleone in Palermo; Editing by Tom Heneghan)