However, Borsellino ran into problems with Chief Prosecutor, Pietro Giammanco. Borsellino was supposed to work on cases in south-western Sicily and Mutolo was from Palermo. There was a risk that this bureaucratic obstacle would jeopardize his cooperation. He refused to talk to anybody else and might retreat because of the uncertainty with the authorities. The stakes were high, Mutolo was probably the most important possible pentito since the defection of Francesco Marino Mannoia in 1989: he had been a cellmate and driver of Totò Riina.