Tenants add wall to make it a 4 bdr

[Michael L.]

I have a rental near a college town. I just found out that my tenants decided to build a wall and put in another door in order to accommodate another person. Looking at the wall and the door it looks professionally done and adheres to my standards. In a way this helps me because now I have a 4 bdr house instead of a 3 bdr but my question is to go after the tenants that built the wall since it was built against my knowledge?