First, of course, the parents and/or other relatives of the groom, who make the dowry demands. Shame on them for placing a monetary value on their son as a husband and then putting him up for sale. For trying to take advantage of a woman's inferior position in our society. For trying to fleece the woman whom they should think of as a daughter.
But the one who is most directly responsible for the crime is the husband. He is to blame for asking his wife's parents to pay him for marrying her, for putting his own services as a husband up for sale. For committing such a crime against someone with whom he is entering into what should be the closest, most supportive relationship.
Every woman should also take responsibility for herself, and refuse to be a victim. It's sad that educated, urban women (who should be less vulnerable) also face such harassment. Why give in to the first demand for dowry? Why marry a person who asks for money as a condition to marrying you? When there are so many cases of dowry harassment, why put your life and sanity at risk and marry someone who asks for dowry? Why not take your life in your own hands and refuse to give in to pressure from parents or society?
But in cases where the victim dies (either kills herself or gets killed), I would blame her parents most of all. Invariably in such cases (from all I've read), the parents give in to the first demand for dowry. After the wedding is over, the groom's family makes more demands. How can someone get their daughter married to a man who demands dowry? Have they not heard of any of the many other dowry harassment cases that get reported (apart from presumably many that are not), of women getting beaten or burnt for dowry? How can they trust their daughter's life to someone like that?
More importantly, what do they do once the harassment starts? How does it get to such a pass that the daughter feels like she has no way out and kills herself? (Or the torture heaped on her increases until it becomes certain that she isn't going to bring more money and she is killed?) Is it not the parents' fault if she can't feel that she could return to them and ask for help when things go wrong? Is it not the parents' fault for persuading her to live with her husband and/or in-laws and saying "everything will be fine"?
If they can come up after her death to allege torture by her husband and in-laws, why did they do nothing while she was alive?
In an arranged marriage, the husband and the in-laws are relative strangers. Their asking for dowry and harassing the bride is a serious crime. But how can parents abandon their daughter and refuse to help, even though they know she is being tortured and harassed?
Which is why I think dowry will not cease until parents value daughters as much as sons, until the love they have for their daughters outweighs their concern about their status in society, until a divorced daughter ceases to be a source of shame.