Real Estate / Problems with recent inheritence in Poznan [3]

Hello,

Recently I inherited an apartment in Poznan from my grandfather. He had a friend who lived there and was "zameldowana na stawo." She was paying him rent and lived there as a tenant. However she is now claiming that she has all the rights to all the property in the apartment and the apartment itself. I know that registry, or zameldowanie does not create property interest. I had some family check up on the apartment a few times. She had changed the locks and I had to pay a locksmith to open the door. Things have gone missing from the apartment and I believe that she is taking my dead grandfather's things and selling them. So far a set of crystal china and a laptop have mysteriously disappeared, and that is just all I know about. She has physically threatened my relatives who check in on the apartment, she threatens to call the police, and screams that an angel told her that she has a divine right to the apartment.

I am living in the United States and cannot travel to Poland to undertake a long legal battle against this lady. Is there any way to de-register her or get her to move out of my property? I would appreciate any advice you might have on landlord rights. As of today she has paid all the rent in the apartment. My grandfather tried to get her kicked out a couple of times but failed because she was paying rent. Please let me know if there is any rights that i have in resolving this unpleasant situation. In advance, thanks for your help.

Marcin