Property of orphaned woman after her death

An orphaned woman who lived near my house and my mother was taking care of her life till death (almost 20 years). She died at the age of 82. While alive She nominated my mother in all his bank account was also taken care by my mother. She died in 2003. My mother and my family did this as service, so we din't care about her property ( only one House). We understand that the house should go to government. But suddenly At 2006 A new person (Who is no relationship with the old women) from next village suddenly took all the house documents and sold the house to Neighbor. He utilities the local guys signature during registration. In the absence on "any" to whom the house belongs to. Kindly advice how to proceed and bring the property to government