Garven is at the Inn in Driftwood. Liam is at X:202 Y:165.
I fed Garven the tainted stew, and now he's running back and forth to the outhouse.
But when I confront him about Liam, and HE attacks ME, I still aggro the whole town. I tried standing as close to the broken bridge as possible and teleport him across it, but when the battle starts, I also aggro the entire town. No idea how to take him out without having to kill everyone.