Based on teh article Zareena is Kabir's murderer, but we don't know any motive behind that besides taht maybe she is kabir's step-mom and felt that azaan and mazhaar were neglected because of him.
So anyways, remember in the begining, there was a promo when the family went to their old haveli and the overhead voice asked what is this raaz that the khan family is trying to hide from afreen? so maybe the raaz is that zareena is kabir's step-mom. Since they never finshed that storyline, maybe they'll continue it with saniya finding out about all these famliy secrets and then she tells azaan and afreen to create a rift btw them. Then she'll act all masoom that she was only trying to help the family and ease afreen's pain over kabir's death, but her intentions are to gain azaan at all costs.
but this will actually bring them together b/c both will grieve together about kabir's death instead of alone.
I'm only speculating, but it's possible :)
What do u guys think?