In the March of Tasuamter ruled by a Confederacy, a character must undergo a Trial by combat.
He has been framed by A collusion of guilds - uses resource control for leverage - and if found guilty of Treason, 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.

March - Similar to a county, but usually a borderland, ruled over by a marquis. Usually heavily fortified due to it's strategically important position.
Confederacy - A union of persons, parties, or states; a league.
Trial by combat - Fight to the death, winner is innocent