In the third year so far of my fortress with 115 population...with only 48 losses so far!

So, when starting the game I had a mayor who was an immediate suspicion, being 270 years old and having grey hair and pale skin. Soon enough, dwarves started being found drained of blood. This dwarf was a legendary weaponsmith, armorer and blacksmith. So, I let him feast a bit while farming him for masterpiece gear. In the end, after equipping my milita with full steel gear, I locked him away and convicted him with 4 murders, 5 witnesses testifying and another 14 unconfirmed murders alone. A small price to pay. However...

After locking him away (the mayor, electable official), I've bricked him in a small 1x1 dark square while in a cage completely isolated from the entire world.

I'm having a bit of a problem now where they keep electing this guy, despite being eternally sealed from society under 5 feet thick brick slate walls and not even talking to anyone or doing interviews. Normally, this wouldn't be a problem, but liasons and other alliances keep wanting to talk to him. How do I get my dwarves to stop electing the ghoul?

Anyways, here's a tour.

The Eternal Mayor:

Entrance:

1st Level:

2nd Level 1/2:

2nd Level 2/2:

3rd Level [under construction]:

The Boneyard:

Would destroying the wall immediately let the elected ghoul out of the cage? Not sure if anyone knows.