The Central Bureau of Investigation is all set to start a probe into the death of DSP Zia-ul-Haq in Pratapgarh in Uttar Pradesh in the backdrop of a growing demand for action against the state's ruling Samajwadi Party leader Raghuraj Pratap Singh alias Raja Bhaiya.
CBI sources said the agency has readied its team which would take over the case as soon as it is handed over to it by the Centre.
They said state government has sent the reference to the Centre which is likely to issue a notification handing over case to CBI.
The sources said notification was expected on Wednesday but due to "technical" reasons it was delayed and is likely to come to CBI on Thursday after which agency could take over the probe.
Zia-ul-Haq, posted as Circle Officer in Kunda town, was allegedly killed by a mob in Pratapgarh on Saturday when he had rushed there after a village head was shot dead over a land dispute.
44-year-old Raghuraj Pratap Singh alias Raja Bhaiya, who has a criminal record and has been jailed before, figures in the FIR filed by the slain officer's wife Parveen Azad in which the minister was accused of criminal conspiracy. Parveen also demanded a CBI probe.
When contacted, Food and Civil Supplies Minister Raja Bhaiya had refuted allegations.