Don't Trust the Mafia(1979)

Montano's corpse is found after being kidnapped by Maurice. The police think then to use the same ways criminals use and to infiltrate Tony Lo Bianco in the gang. Tony is a former FBI agent sent back to Italy for many crimes. Police Superintendent Ferrari disagrees but Tony begins his operations and meets Paulette, the Maurice's daughter. Tony and Paulette find out that perhaps Maurice is not responsible for Montano's death and they discover they have to start a real battle to save their lives.