I think that Bani fully knows everything, starting from the minute she saw Pia's picture on the computer at the telephone place, she put everything together and now she is doing things as though she do not know.
Today's episode made me thinking that Bani really knows, when she did not end her phone conversation with Jai, but rather kept it at the side, deliberately wanting him to hear what's going on.
I can be wrong, but I have a feeling that she knows. What do you think?