I have a theory about this Abhimanyu as well. I am just speculating here, but I feel CVS could make him the reason why Kallu didn't know about Malhar's haalat and Deshmukhs location for so many years. Since they met in coaching classes, they must have known each other for a long time. Maybe he was in love with her and didn't confess cause he failed IPS and she became IAS officer so he was embarrassed. So he decided to make a name for himself in police force and maybe confess later, but till now he's only inspector. So I'm sure he's tried some illegal ways to get ahead, maybe join drug gang and then bust drug gang?