The CBI also wanted to know who was killed first - Suresh Yadav, the brother of slain gram pradhan, or Haque - and what precisely went wrong.
The CBI has sought custody of two accused - Guddu Singh and Rajeev Singh - arrested in connection of DSP Zia-ul-Haq's murder. Both of them were arrested by the UP police
The agency has now pinned its hope on electronic data and sought call records of all accused, including Raja Bhaiyya. The agency has also launched a helpline to collect information from eyewitnesses.