• Land encroachment issue

Hello Sir,
I am writing this query to enquire about what steps we should take to prevent my neighbors who actually are my uncles from encroaching our land. So, my family comprising me ,my younger brother and my parents belong to calcutta and we own a land there which is under my parent's name. Both my parents were working and so we had to stay away from kolkata for a long time. But after they retired they planned to reside at kolkata and so my father build a house there on our land. But unfortunately my elderly parents are facing a lot of issues there from my uncles since they started staying there for a year. both me and my brother are employed abroad and so we are really worried about our parents safety. so the issue is that my uncles have encroached upon a part of our land by creating a kutcha drainage system on our land instead of creating a line with municipality high drain wihch is just a few meters away from there house. My parents have tried complaining about it to the municipality councillor as well as to the chairman but they havent really done much because of the influence of my uncles family in that area. the drain has been creating a lot of nuisance for my parents and specially in the monsoon season because of the drain overflow they had snakes in their house. when my father opposed them from deepening the drain further he was beaten up by my uncle's sons. So, he went to compalint to the police and because he went to the police my cousins disconnected all our water supply lines. the councillor and the chairman hasn't been of much help. me and my brother are really worried about our parent's safety. my father doesnt want to lodge a criminal case against them because they might come out of the jail and take revenge on my parents and even me or my brother wont be available to take care of them. any suggestion in this matter would be of great helo.