Abandoned Homes

We have recently purchased our first MHP. There are two homes on the property that are abandoned/vacant and the previous owner claims that he does not know who owns of the them. I would like to know what we should do about claiming ownership of the homes. One of the homes is vacant and the owner has not paid rent since July 2011. This particular home, we do have the owners information on. The other home is abandoned and we have no clue who the owner is. Please advise.