harrasment from my fathers family

Hi I am an alone son to my parent'sI lost my father few years back me and my mother After my fathers death a younger brother of my father is been troubling us over the property claim and mental harrasment to my mother . we have a land in tamilnadu 3 acers were it is been subdivided 1acer to myself and 1.5 acers to my mother .50 to my fathers brother since he is a neabiour to us he is been troubling us to encroache the land he is not allowing us to do anything in that land. We tried to solve it ammecibally were a wine store was in my mom name which was giving to him inreturn he would not trouble us he has given a letter stating he would not claim on anything with rs100 bond. Now we have house in that place that is been used by him we have been telling him to vacate he is not vacating the house he any how does not stay their.he is in bangalore it locked not been used rather letting us use he trys to bribe he trys bribe everyone in the office does not allow us enter the land my mother is deeply harrasment by him of thretening kindly suggest wat action can be taken against him regards naveen