The movie Investigation of a Citizen Above Suspicion, directed by Elio Petri in 1970, follows the story of a high-ranking detective named A. (played by Gian Maria Volonté). One evening, after spending the night with his mistress Augusta Terzi (played by Florinda Bolkan), A. strangles her to death.
From that moment on, A. sets out to prove his own guilt while remaining above suspicion due to his position of authority. He begins tampering with the evidence and planting clues to lead the investigation towards him, ultimately becoming more and more reckless in his actions.
As the investigation progresses, A. finds himself gradually more obsessed with proving that even someone as powerful as himself can be punished for a crime. He begins to challenge the assumptions of his fellow officers and push for a more thorough investigation, all the while knowing that he is the true culprit.
The film is known for its sharp critique of Italy's political system at the time and the abuses of power it allowed. It won the Academy Award for Best Foreign Film in 1971 and is considered a masterpiece of Italian cinema.