I found out that, though my latest city of my project has a courthouse, it didn't have a police station yet.
So I went doodling and lo behold, there came a quite malicious design into mind.
It's a police station with a watchtower (because in my city, police are alerted through flags and light signals from guard and watch towers), an outside jail for the people who are trialled by the public, a small ground floor jail (for beggars and drunks), a sheriffs office on the ground floor, a waiting room and underground prison cells for the real criminals.
The underground prison also has two torture chambers: One with a couple of waterboarding chairs and a variant of a 'copper ox' (a device in which a criminal is placed after which the device is heated up by a fire underneath it). The second has four iron maidens that can not be left once you step inside.
The underground part is partially made of obsidian, to prevent prisoners from tunneling out. The obsidian parts are also cloacked on the outside with an underground lava moat that's invisble from above ground. This is to prevent criminals from digging prisoners out.
The entire project includes the underground part so you'll have to nudge the schematics several blocks down. Just os you know...