Why is it that I have this snaky feeling that a Private Investigator (PI) has been hired to tag Tanveer???
The PI could have been hired by Rashid because he fears for Zoya's life. He has understood Zoya for who she is more than Asad has done. This could lead to the track of Rashid's redemption with Zoya for setting fire to the factory unintentionally burning Zoya's mother... and it could also lead to the reunion of Rashid and Asad.
The PI could have been also hired by Asad (which I somehow not sure because of the Ajmer track) and he did so because he gave Zoya a benefit of a doubt... When Zoya said her mehendi burns was due to allegry, he expression said that he did not really buy her explanation. This lead to the track that he did trust Zoya but he did not want to alert Tanveer of this.
What do you think?