"Both SP and BSP provide outside support to UPA government. Now it all depends on the central probe agency (CBI) as to how it wants to carry out the probe. If investigations are carried out in a fair manner, the truth will come out," he told reporters here.
"The role of CBI will, therefore, be observed keenly," he said.
Singh demanded fair and transparent probe into the murder of DSP Zia-ul-Haq in Pratapgarh district in which former UP minister Raja Bhaiyya has been named in one of the FIRs.