First, you don't have the right sign out. Get one of the fab shops here among the NC4x4 crowd to build you one. A nice one, but not too fancy. Say a thousand dollar yard sign. Be sure and save the receipt.
Then it's felony theft in NC (over $1k).
Don't forget the little box in the frame, to hold one of these: https://www.amazon.com/AMERICALOC-G...d=1543022039&sr=8-4&keywords=gps+tracker+mini
1. Wait
2. Tell the cops where to recover your sign
3. After sentencing, offer to buy his equipment for ten cents on the dollar
I don’t think you’re going to get a better idea than this, from a legal standpoint.