Savage Three (1975)

By day, Ovidio (Joe Dallesandro) and his two friends work at a data center. After work, they blow off steam by committing random acts of savage violence, swiftly graduating from sparking a riot at a football game to vehicle theft, rape, and murder. The police are convinced this recent spate of crimes is politically motivated, but world-weary veteran Commissario Santaga (Enrico Maria Salerno) suspects a far more terrifying explanation: that these young men are motivated by nothing more than boredom and disaffection at civilized society. As Ovidio's behavior escalates, a psychological game of cat-and-mouse ensues between the two adversaries, building towards a shocking final confrontation.