Why not just introduce a chance that you're going to get caught while you are stealing and get rid of the interrogation afterward? When trying to steal from someone, instead of seeing "Needs Thievery 2" or whatever, you can always attempt to steal and then there's a check to see if you're going to get caught right at the beginning and when stealing each item. The likelihood of getting caught would be related to:
-the difference between your Thievery level and the level you would have needed to steal (is this based on Wits?)
-the number of other NPCs in the immediate area; even if they aren't directly looking right at the moment, stealing in a crowded market should be riskier than stealing in an empty alley
-maybe the weight of the item being stolen?
So, if you get away with it, you get away with it and you aren't bothered again. If you get caught, you get caught once and fight or talk your way out of it. Maybe there will be one or two places in the game where it would be particularly interesting to have them try to track you down; keep those then. It doesn't necessarily have to work exactly the same everywhere.
