In the Duchy of Tuaequodni ruled by an Oligarchy, a character must undergo a Trial by combat.
He has been framed by A cult or brotherhood - bound by a mission and code - and if found guilty of Murder, his punishment will be Bestow Curse. The prisoner loses 6 off his ability score. That is devastating, possibly cutting it in half or worse. Forcing them to become an imbecile is a good way to keep the person useful doing menial chores without needing high security. The GM can also craft their own Curse effect, such as 50% chance of lying down every six seconds - it’s hard to escape while taking a siesta.

Duchy - The dominion of a duke, who is the highest ranking noble not in the royal not in line of succession.
Oligarchy - Oligarchy is a form of government where political power effectively rests with a small elite segment of society (whether distinguished by wealth, family or military powers).
Trial by combat - Fight to the death, winner is innocent