Victim of Fraud and Circumstances

Dear Sir/Madam: My father in law has two sons and one daughter. My husband is the elder son of the family. Soon after the birth of my first daughter my brother in law planned a conspiracy against us and was succeeded in getting rid of three of us. As a result I along with my husband and new born daughter left from our my husband's DDA flat where we were living as a joint family along with my mother and father in law and lived on a rental place for a short period of time. Our relationship with my parents in law and my only sister in law remained very normal but my brother in law we later realized that his main intention was to break his relationship with us for ever. In our absence my brother in law asked his father to transfer his land on his name for the purpose of applying loan from his employer for the construction of the house. At that time this land was although on my father in law's name but the 50% land of the same was of his sister. Unfortunately there was nothing on our aunt's name in writing but verbally as they invested equal amount and were 50% shareholder of the same. It created a big dispute between my father in law and our aunt (my father in law's sister), somehow later she gave up her shares and may father in law paid off the total amount plus interest to his sister she was a widow at that time. In fact after the transfer of the land without informing to our aunt and even to my husband who is one of the hairs and the first child of the family, my brother in law started constructing his house on the front part of the land, and left the back part for our aunt and our aunt didn't agree and later she gave up her share. For a long period of time that part remained inbuilt and later in my father absence my brother in law covered that area too and extended his house without any consideration for the share of my husband or either for his sister. Now at last we came to know that all the formalities like transfer in DDA, Gift Deed has been finalized on my brother in law's name and by law we can not demand our shares at all. It is a huge land and value wise we can't afford to loose our shares. In short kindly let me know if the land was gifted to my brother in law and if he is the wholly solely owner of the land in the documents, can we challenge his rights as I have one hand written letter of my father in law stating that he tried his best to get our share from him but he doesn't want to listen and we should try on our own. My father in law passed away in September last year and we have been residing in USA since 1993. We really need our share but wondering how to challenge his right when first of all he grabbed this land from my father in law , our aunt and at last from us and my children. He has committed a fraud and crime as well since my mother in attempt to suicide due to to the mental, emotional tortures from this son and his wife. .