Palermo, May 21 - If Italian President Giorgio Napolitano is called to testify into alleged negotiations between the Italian State and Mafia 20 years ago, he cannot be questioned on information found in wiretaps that were legally destroyed, the head of the appeals court in Palermo said Tuesday. One day earlier, the court gave prosecutors the first green light to call Napolitano to testify at the trial into alleged secret negotiations between the Mafia and the Italian State in the early 1990s. The president's name appeared on a witness list of almost 200 people being reviewed by a panel that may ultimately rule out calling the president to testify. But if Napolitano is called, he will not be asked to discuss telephone conversations with former interior minister Nicola Mancino, said Appeals Court President Alfredo Montalto, who added it was "legitimate" of prosecutors to add the president's name to their witness list. Those conversations in late 2011 and May 2012 were intercepted during the investigation of the alleged State-Mafia negotiations, but the tapes were destroyed by order of the Constitutional Court on appeal from Napolitano. It has been alleged that in the early 1990s, State officials negotiated with Cosa Nostra in a bid to stop attacks after a long campaign of violence that culminated in two bombings in 1992 that killed anti-Mob prosecutor Giovanni Falcone, his wife, fellow prosecutor Paolo Borsellino, and several bodyguards. Napolitano's testimony has been sought by two civilians with a special interest in the mafia: Salvatore Borsellino, brother of slain prosecutor Paolo; and MEP Sonia Alfano, who represents mafia victims.