Couldn't the culprit be shazia.Because the way she instantly pushed the blame towards zubbu in front of the police was suspicious.It was like she had already planned it and knew what to say when the watch was showed.
Well as they show is showing that there is something cheesy about Zubair so I think that it is Zubair coz Chand bi cant do that and others like shazia and rizwan are the least. So I think it is zubair. And besides the blaming thing is because she doesn't like Zubair at all and wants him to be arrested and out of the house and if he is related to Aaliya so she hates Aaliya too. So I don't think it can be shazia or rizwan. It can only be zubair but because of the 'dark past' of Osman which is about to be revealed. I just hope Zain and Aaliya stick to each other on this mystery.