I saw the preview yesterday, which showed that kala has poisoned supriya's sari. I think any smart villain will not do it especially when the first incident of putting poison in AC just happened and dutta is still looking for the person who did this plus on top of that he did suspect that the person who did all that is someone from their own house. therefore, by doing this kala will prove that what he is suspecting is true. i think kala will be dumbest villain if she did this the very next day of what she has done just day or 2 before.
Sorry if someone has already posted this before