It's called Investigation of a Man Above Suspicion (Indagine su un citadino al di sopra di ogni sospetto) and somehow I had never come across it despite it being right in the wheelhouse of all my obsessions and interests. Plus the soundtrack is by Ennio Morricone(!) I loved every frame of this film. It's carried by the performance of the lead actor Gian Maria Volonte who plays a loathsome police inspector who conducts a gruesome  thought experiment about power, lies and corruption. It's ostensibly a crime thriller but that's just the icing on top. Underneath it defines a certain kind of struggle that threaded its way through most of the 20th Century and continues to define our society till right now. The chief represents the Law and Order At All Costs faction who is surrounded by a protective scaffolding of lackeys, enablers and entrenched power eagerly willing to justify its repressive tactics. It climaxes with an incredible scene in which guilt and innocence are confidently treated as interchangeable according to circumstances. The police chief's mood swings between a swaggering sadistic confidence and crumbling self doubt, mirroring a society that was then splitting down the seams.  It's part of director Elio Petri's "Trilogy of Neurosis" focusing on Power, Work, and Money, the three-headed monster of contemporary western society. I can't wait to track down the other two.