Psycho behavior of brother in law

Respected sir, my sister got married to (sreenivasulu) a year ago before the marriage he behaves like so decent person , but after 1 month his real behavior came out and he claims doctor check up for my sister that he has doubt on my sister later he said that we didn't go to see her talk to her, he claims that he only see, talk to my sister and he also had a hobbit of drinking and whenever he drinks he used to beat my sister saying that if itsnt you I should marry other girl and he used to torture her mentally , my sister is so innocent girl like all innocent wives that are loyal bound to her husband she wants him but he doesn't he also beat my mother 2 times , so we are got tired of all this things and we took my sister home and later all elders talked and convinces us it will not repeated and so by believing them we send her but he doesnt change and he started beating my sister more and he does not have respect towards elders, arrogant, drunkard, cunning, psycho, playing double games, liar, changing colors a/c to situations ,now we wanted to get rid of him and we wanted to file a complaint against him and we do in kalikiri police station, after the day we had given complaint don't know what happened to the police and they called us for enquiry and my brotherin. Law and his family comes and he beats my mother there in front of the police but they can't do anything and instead they are supporting them what can we do sir??????? Now we are very clear that she doesn't live with him and wanted to get rid of him please help us sir our family lives depends on ur help and justice sir