Palermo, March 4 - Mafia boss Bernardo Provenzano is not fit enough to testify at a trial into alleged negotiations that took place some 20 years ago between the State and Cosa Nostra, experts said Monday. Renato Ariatti and Andrea Stracciari were appointed by the court to assess Provenzano's fitness to take part in the hearings into negotiations that reportedly occurred during the 1990s between the national government and the mafia. The judge's ruling on the experts' findings is expected Tuesday. Provenzano, 80, is seriously ill with Parkinson's disease. The complex case regards an investigation into suspicions that high-ranking politicians and police negotiated with Cosa Nostra to try to stop a series of bomb attacks that claimed the lives of anti-mafia judges Giovanni Falcone and Paolo Borsellino in 1992. Charges against Mafia chieftains range from violence or threats to the political body of the State to mafia association. Arrested in 2006 after 43 years on the run, Provenzano is in declining health, which his lawyers blame on his isolation in maximum-security jails, almost entirely cut off from the outside world in order to prevent further criminal activity. The ex-mafia chieftain is serving life for various murders including ordering the fatal bomb attacks on Falcone and Borsellino.