Another lost story with a memorable fragment. A man is held captive in an authoritarian country. He was once an important man but has fallen out of favor, and he will be executed at a time of his captors' choosing. As it turns out, they give him days to think, and he has many conversations with the man he presumes will be his executioner. The waiting is itself a form of torture. Perhaps they do not know the full details of his crime and are waiting for him to incriminate himself.
The science fiction element of the story is that this is a variation on the Unexpected Hanging Paradox, in which a prisoner thinks that he has deduced that he cannot be executed without the captors' violating their own schedule. In this case, the prisoner begins by believing that he was guilty, but eventually convinces himself that he was innocent. Now he is certain that he will never be executed. When he expresses this, his captor smiles and prepares to shoot him. "When you are innocent, then you are guilty," says his executioner.
I very likely read this in an English-language science fiction anthology in the 1960s or 70s.