In the Margraviate of Quorum ruled by a Theocracy, 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 Spying, 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.

Margraviate - A borderland ruled by the margrave who has military responsibilities. Usually larger than normal counties due occassional expansions at the borders.
Theocracy - Theocracy is a form of government in which a 'god' or 'deity' is recognized as the supreme civil ruler. For believers, theocracy is a form of government in which divine power governs an earthly human state, either in a personal incarnation or, more often, via religious institutional representatives (i.e., a church), replacing or dominating civil government.
Trial by combat - Fight to the death, winner is innocent