One of Them Is the Murderer (1971)

Marek (Jirí Holý), formerly a driver of a long-distance lorry, has served his term for smuggling art works abroad and is released from jail. Years ago, he sacrificed himself and confessed his guilt on behalf of his companions - the drivers Krása, Jelínek, Hess and Novák from the Ministry of Culture who gave them tips. Marek finds Hess and tells him that now he expects the gang to compensate him for the wasted years of his life. Hess pulls a gun on him but Marek unexpectedly disarms him and shoots him dead. He confesses his act to the other companions and, through blackmail, manages to receive from them a regular rent.