This is a bit of a sticky situation, but here it is:

My girlfriend recently purchased her recently deceased parents home in March 2007. The house is in Philadelphia, PA.

A month prior to her purchasing the home, the house was found to have a gas leak, so my girlfriend's sister (35 years old) who was living in the house (rent free) came to stay with us in our apartment, since she had no where else to go, and little means to support herself.

During the time the sister was staying with us in our apartment, my girlfriend bought the house (March 2007), and we hired contractors to make many repairs and improvements to the house.

It is now June, and all renovations and repairs have been made to the house. We have now moved into the house, taking the sister with us since she has lost her job and has not yet found work.

The sister has become defiant and disrespectful to both my girlfriend and me. The sister does not contribite to the household. When she was told recently that she could not bring friends into the house until we were finished with decorating and unpacking she launched into a drunken tirade (yelling, slamming doors, breaking household items, etc.).

When we told her that this living situation is not going to work, and that she has to leave, she refused to go stating "This may be your house, but it's my home."

We would like to know how what steps/legal options we should follow to get her removed/evicted from the property.

I have been told by some police friends of mine that we can not have the police remove her, because she has "established residency" at this address from the time when she lived there with the parents (pre-sale to my girlfriend).

Any help that you can give would be very appreciated...