Razvyazka (1969)

A team of Russian special agents is investigating a murder. Among many suspects they detected a man, who is slightly unusual in his behavior. He is smooth, fast, very careful and very nice. His name is Sotnikov. He is the spy. When there is enough evidence, and the timing is right - he gets arrested. When taken to KGB for interrogation, he is confronted by the group of interrogators with so much evidence against him - a gun, a radio transmitter in a briefcase full of explosives and other spy gadgets. Now he belongs to jail for life without a right to amnesty.