i have full sympathy. it is not the time to weep and wipe tears. it is the time to act decisively and very decisively. the first step in that direction is to engage one of the best and criminal lawyer at bangalore. the issue here is not to find out whether charge sheet has been filed in the court or not. the issue is that how the accused shall be convicted and for that what we have to do, so that our sister gets justice.
the case is criminal case. in the criminal case, your sister's side will be represented by State, i.e., public prosecutor. the accused will certainly engage a very good advocate, as the case is tried under very serious charges, i.e., Section 304 B , 498-A and may be section 302.
In these cases, the accused and state generally will have hand-in-glove (colluded). take care. the state's counsel himself will try to dilute the case and bring contradictions in the evidence of prosecution, which will benefit the accused. take care. so, i am suggesting to engage a very, very, and very good advocate to get justice to your sister.
first obstacle comes in your way is that your advocate is not allowed to effectively and directly intervene by the judge and your advocate is advised by the judge to assist the PP (public proseucter). even then, if you have a good advocate, he will turn around the situation by approaching HC at interim stage of the trial and get favourable orders about conduct of trial and it will give impression in the mind of the judge and PP, that you mean business. they cannot take this trial lightly.
after filing of the charge sheet, charges are framed. If the charges are limited to section 304-B and 498-A, then your advocate has to try to get included the charge u/s 302. after that prosecution evidence starts. your advocate has to get your witnesses be properly trained for gruelling cross examination on the basis of the documents available on the record. proper training is required. otherwise, accused will be acquitted.
i have not asked you whether the death is related to dowry demand or not. it is a very important fact and your advocate takes care of this thing if you engage a good advocate.
wish you best of lluck.