what care should taken before leaving husband for being harassed

my sister married around 3 years back and staying at bangalore with her husband, she is earning, her husband assaulted on her (shouting,slapping, abusing to her and family members, asking her to leave his house, asking for divorce etc.) for dowry, he always misconduct her saying he was cheated by her and her family members. however she is very passive and tried a lot to save her family but her husband,s cruel behaviour getting stronger day by day, today itself my sister called me and told that she was slapped again and told to leave his house, either live with him under his alike domination. my sister is very much afraid of her husband. even she dont want us to talk to her husband or any of his family members as her husband will go furious, and will be very cruel with her. we family members lives here in jabalpur (m.p.) it is not possible for us to provide any instant help to her in any critical situation. now she has no other way but to leave her house to escape from this cruelty. i want to know how to safely leave his home and what legal prepartion should be done before she leaves her house. we are willing to file a case against his husband here at jabalpur, is it possible that the trial be held here in jabalpur. where we should file a complaint.