Amid growing media scrutiny, the then UP Chief Minister Mayawati handed over the case to CBI.  

A CBI team under Joint Director Arun Kumar concluded that murders were allegedly committed by Krishna Thadarai- help at Talwar's clinic, his friend Rajkumar—a domestic servant with Praful and Anita Durrani who were Talwars' friends, and Vijay Mandal, driver of Talwars' neighbour.  

These findings were trashed by the then CBI Director Ashwani Kumar who poked holes in the theory by underlining loopholes in the arguments given by Arun Kumar.

In September 2009, Kumar constituted a new team under Joint Director Javeed Ahmed and the then SP Neelabh Kishore to look into the case afresh with freedom to choose their team members for the case.