Armed with mobile phone call detail records of former minister Raghuraj Pratap Singh alias Raja Bhaiya and other accused in the murder of DSP Zia-ul-Haque and two others, the CBI focused its probe on the controversial politician's associates on Tuesday.
The agency picked up three associates of Raja Bhaiya for questioning from Purney Mau village, which is adjacent to Balipur village where Haque was shot on March 2.
The trio was questioned after the CBI assessed the call records gathered by the UP special task force.
Meanwhile, a CBI court remanded two aides of Raja Bhaiya in the agency's custody till March 18.
Haque was killed while trying to control the violence that had erupted following the killing of Balipur gram pradhan Nanhey Yadav.