This seems to be quite a strange situation. Based on the understanding on the situation, the first step would be approach the labour court with the copy of the resignation letter or resignation e-mail she had put across to her superiors. This is to confirm that the resignation was voluntary and also to avoid situations in future where the company makes her withdraw her resignation now and after a while terminate her services making the exit involuntary.
If there is any aggression observed it would also be better for her to approach the police and the women's rights commission as well for protection. This could be done after she registers her resignation documents with the labour commission and provides a complaint.