Citizen X is an American drama. If it depicts what you're saying (I've seen it but can't remember it) then it's just another Western dramatization depicting post-Stalin Soviet Union in cliches from the 1930s.
In the real life case Citizen X is inspired by[0], nobody was tortured for a conviction, even the guilty man, who was simply put into a cell with a police informer to gather information and questioned normally by investigators who only had ten days under Soviet law to release or charge him.
[0] https://en.wikipedia.org/wiki/Andrei_Chikatilo
