On my current fortress I noticed a couple of necromancers when I started. I killed one, and another got away. Now body parts are getting up and dancing a jig with my dwarves, but I can't see who's raising them. How can I find the lovely individual who thinks the dead should rise again?
Just to prove I have a stealth necromancer, he just popped up:
And when I zoom…
Best Answer
Set a number of cage traps around the map; The Necromancer will eventually walk into one. Then, once he or she is trapped in one place it becomes trivially easy to find him or her.
To cut down on the number of undead hands filling your traps you could place a row of weapons traps in front of your entrance, before the cage traps, to clear out some of the riff-raff.
My understanding is also that Necromancers will hunt down living creatures, so you could try baiting your traps with a chained animal at the centre.
Note; I wrote this after discussing it in comments with the OP, and him discovering that despite misgivings the Necromancer was eventually caught in a cage trap.