Family fights regarding property

I am a simple housewife. The house in which we stay was actually belonged to my parent- in-laws who has transferred the house and land in the name of my husband (their elder son) on their own will. after their death, I have purchased the house and property from my husband, but I still allowed my brother- in- law to stay in our house without any agreement. My family and my brother in laws share the same house, since the time of our parents. However since the last 7 years, there is an unending family despute going on and now they are demanding a 50% share in all property. We still don't want to throw them out in the streets because they have children, and they are taking advantage of our goodness by making renovations and construction without my consent. They also involved in practical fighting with my husband, and even threaten to kill us. They seem to have bribed the police also. Sir, I am ignorant of the law and dont know exactly what to do, we are helpless because my brother- in- laws family is richer and also have the local political and bad men contact. Even our family lawyer is afraid of their power. I want to stop the illegal constructions as well as the fightings with the help of law. I also want them to vacate my property now. Please state me what kind of articles and lawsuits can I apply on them so that they may be punished and my family be safe. Is ipc 107 a good enforcement for the stopping of the constructions and brawl ? I am waiting for your valuable advice. I want them severely punished.