In the County of Untire ruled by a Democracy, a character must undergo a Trial by combat.
He has been framed by A monster or group of monsters - mind flayers, a beholder, giants, a dragon - and if found guilty of Embezzlement, his punishment will be Symbol of Death. Cast Permanency, place the symbol so its 60 foot radius crosses the only entrance. Cast Curse on the prisoner to lower their saving throw. This still gives the prisoner a chance at a saving throw, so you will want to target those with naturally poor Fortitude, and this is better as a deterrent than a cell because the desperate will take their unknown-but-poor chances of surviving, sometimes. Substitute other Symbols to create other defenses in the prison.

County - The land ruled over by a count (or earl, in some areas).
Democracy - Government by the people, exercised either directly or through elected representatives.
Trial by combat - Fight to the death, winner is innocent