What can be done if property has been sold through GPOA

My father purchased a piece of land in my mother`s name in the year 1985 in Bihar which we have complete registry paper since then .In February 2011 my mother passed away.As we are working outside ,we took our father with us out of the state. In April 2011 two people arranged General Power of Attorney from one of our neighbors who sold all her property and shifted to some other city.These two people on the basis of the GPOA from her further sold and made registry to one of the accomplices`s wife. We have challenged the above Power of Attorney in the court.The Honourable court has issued Non Bailable Warrant(NBW)against the lady who has given the said power of attorney and not being available in the court despite several summons.No body knows her whereabouts and police also could not trace her during these 7 years. They tried to capture many a times using muscle power.Though we have Land possession certificate from the circle office. What should be our course of action now?