What to do

Hi This is regarding my sister's marriage recently happened. Just after few days, we started getting trouble for dowry. here is what happened in short... Groom's proposal came through someone who was involved in a mission called Dahej Mukt Bharat and by photo and profile we liked. Just after engagement, groom's family asked for money and we hesitated but they started forcing else marriage will not happen. As engagement was already done, we did not want to stop marriage but hesitant to pay but at last by force we paid. After marriage, as soon as girl went to groom's house, they started torturing for things to get from our home and started asking for girl's money, what she is earning also. She is a teacher in home town. Boy started treating her badly, he started abusing by words and threatened for life and started talking everything against her family and so on many things... After she felt wrong about things and mentally harassed, she told us and we asked groom side to sit and talk but they are not agreeing. Later we inquired about the boy, we found that the bio data he had sent, he has written profile description, he has not even worked as he mentioned, it came out to be fraud. Now my sister is very much scared to go with him after he treated her badly and threatened her for life and daily abusing. Boy's father is a lawyer in same home town, now we need legal opinion what to do in this case, girl cant stay with him as we feel life threat and security has become a main reason. Should we approach police or go for court case? As his father is already a lawyer, he will have influence in same court that we worry. Please suggest what is the way so that we can get out of this relation and get separated legally, court case or police case and what should we do next for separation/divorce. How soon we can get. Please advice