Local goons creating obstacle in construction on my land

Sir I am Ranjeet Shahi, living in Chandigarh. I have a small piece of land in my parental village in Nalanda district, BIHAR. This land was purchased by my grand father in 1968, I have sale deeds and the revenue receipts upto 2016. My father, who is a retired govt servant, 75 year old, live in the same parental village. Recently when he tried to get the boundary wall constructed on the land some local goons came and restricted the construction work claiming that this land belong to them. My father approached to C.O (block) and SHO, but all his effort gone in vein and no one helped us. Now I guess that those goons have backing of local police and C O as well and they all are concocting a plot to extract ransom from us. I dont want to indulge in a lazy legal process because I live in chandigarh, an academician, have no time to go to Bihar frequently to attend court proceedings and health of my father do not allow that. Please suggest what shall i do to protect my land from being garbed by those goons.