Dowry Harrsement & Domestic Violence by husband.

Gud Afternoon Sir, My name is Zain,Five years back my sister got married and her husband met with an accident by doing some illegal activities.After recovering he n his family torturing my sister for asking money and continuously beating her and hurting her with their words.In last month he threatened our sister that he will kill her and so we family decided to bring her back to our home and on the way he attacked us by beating us and thrown stones on us to kill us.After happening these incident and three days back he came to our house n threatened all our families and kidnapped four years child from us.At that time only we lodged complaint against him on police station and the in charge inspector didnt even interrogated them and supporting them fully.In final decided that they accpeted that her husbad will not come to our house surroundings if he came they are responsible for the causes.Now i want an agreement that legally that he wont come after us pls help with legal points