Threatening to commit suicide and forcing for marriage

Respected Sir /Maam, I am a 30 years old single working man living in Mumbai. I was in a non sexual relationship with a girl from the same city from June 2012 till January 2013. The girl initially was very nice and loving towards me but over time her behaviour started to change gradually and started becoming very controlling and abusive towards me and me undergoing physical abuse at her hands at times. I realised that she was suffering from some mental disorder and used to behave that way due to it. She started blaming her broken family for her behaviour. I talked with her family over this and requested them to take her for psychiatric treatment which they did not pay heed to. Over the time the relation turned very toxic and unbearable for me and I had to take the extreme step of filing an N.C. with the local police station against her as she started threatening suicide and leaving a suicide note in my and my family's name if I did not adhere to her demands. The police were very supportive and helped me by getting a letter signed from both of us in front of our families as witness saying that we will not get in touch with each other henceforth. After few months I started getting apology emails and phone calls from the same girl and assurances that she is taking steps to be a better person and want me to be in her life as a friend and guide ( I have the copies of the said emails and chats with me ). Over time my anger mellowed down on her and I decided to give another chance to this relationship as I felt that she was truly repenting and had genuinely mended her behaviour. We got back together in June 2014, but over time by now she has returned back to the old ways of behaviour and has started verbally abusing me as of now. She has not physically abused me yet but is threatening suicide and also written notes in her diary stating me as the reason of her death which she has shared a picture of, has started questioning my sexuality as I have not maintained any physical relation with her this time too and threatening to destroy me and my family's life if I do not adhere to her demands. Her demands are 1) Get married with her at any cost, 2) Not to live with my parents after marriage (I am the only son), 3) Maintain her lifestyle as she doesn't want to work post marriage I have the following evidence with me: 1) Picture of a written suicide note 2) Chat sessions back up which threaten suicide and forcing for marriage 3) Medical record of her doctor stating that she is undergoing severe stress and depression 4) Emails sent post Jan 2013 expressing her apology and stating that she just wants friendship and no relationship Please advise on the further steps to be taken. Thanks.