A rowdy is harassing my sister and family with physical

A guy was stalking my sister and forcing her to lover her and following her to all the places by creating threat and panic situation .. eventually torturing her to the core. We then complained to police and then they have warned him and sent back.. And slowly after few months he was back with the similar torturing activities even to the family members.. Making rude talks and scolding us in public with filthy language and also created false stories about my sister that they had affair to some of our neighbours... As a respectful family living in the locality for more than 60 years.. We were humiliated and i couldn't console my sister and parents. We then moved to police station again .. They had simply warned him and told us that they had made an CSR and the family members of the culprit fell on our knees and asked us not to file an FIR.. Also they have ensured this will not happen again in future. And so we left without filing the FIR. Months passed away.. The activities started gradually .. again and today he drank and shouted infront of our house in public and also threatened me ..that he would kill me one day and thrashed the motor cycles .. Took out the air after we closed our gates. We are basically a middle class family and looks like police is also of not great help to us. Would be great if you can suggest me in the right approach to be made.