Z opens with the following claimer: any similarities to actual persons or events is deliberate. This is because this classic political thriller and police procedural by Greek director Costa-Gravas (Missing, Mad City, Amen to name a few) is based on a real story. Z is basically the re-creation on film of the true story of the assassination of Greek MP Gregorios Lambraki, the political cover-up behind the assassination, and, in the end credits, the military coup that gave Greece a military junta.
Yves Montand plays the MP and peace activist who is killed by two thugs in a delivery scooter. His associates claim murder; the police and government claim an unfortunate accident. Jean-Louis Trintignant is the investigating judge (sort of a DA) who is looking into the case. The more he looks into it, the more witnesses are threatened and the more higher-ups in the government become implicated in the murder. As he comes closer and closer to the real truth and not the official version the government would like him to arrive at his higher-ups apply more and more pressure on him. It is finally left up to his conscience and this is where Z becomes most biting with Trintignant's "name, surname, occupation" deadpan delivery to all the witnesses from the government.
Admitedly, the first half hour of Z are a bit confusing as you are not quite sure which of the people in the public square are peace activists and which are fascists. There is also the mystery of what happened to the first guy to clobber the Montand character and how much this had to do with his death.
It is interesting to note that many of the people involved in Z such as Costa-Gravas were in forced exile from Greece at the time of its filming (the military junta took over in 1967) while the score by Mikis Theodorakis (Serpico, Mist) was snuck out of the country as he was under house arrest.
The end-credits to Z are most telling as you get the story of what happened to all the people involved in the case.
Z won two Academy Awards: Best Foreign Film (Algeria, this is a French-Algeria co-production) and Best Film Editing as well as nominations for Best Director, Best Writing, Best Picture.