La polizia ha le mani legate (1975)

At a hotel in Milan, where an art conference attended by representatives from many foreign countries is under way, a bomb explodes, causing several deaths and injuries. Commissioner Matteo Rolandi is at the hotel, having made his way into the room of one of the guests present—a drug trafficker—who also falls victim to the massacre. A few hours later, his colleague Balsamo happens to encounter the bomber, Franco Ludovisi, who manages to escape. The following day, Balsamo is killed by a mysterious assassin. The official investigation is assigned to prosecutor Di Federico, but Rolandi tries on his own to find those who ordered the massacre and his colleague’s murder. Whenever he manages to find a promising lead, the people the organization considers inconvenient are immediately eliminated. In the end, it emerges that the organization has roots even within Milan’s judiciary. Di Federico therefore gives up the case, while Rolandi continues his investigation. Rolandi discovers that the killer is one of the people involved in the massacre, and kills him himself.