Lucknow, March 7 (IANS): The Central Bureau of Investigation (CBI) is likely to begin a probe into the murder of Uttar Pradesh deputy superintendent of police (DSP) Zia-ul-Haq and two others Thursday, officials said.

The "request letter" by the state government reached the CBI office late Wednesday, following which an approval was sought from the department of personnel and training (DoPT), said an official who did not wish to be named.

Following a go ahead, the CBI formally registered a case in connection with the killings of Haq, village head Nanhe Yadav and his brother Suresh during violence at Balipur village in Pratapgarh district, some 100 km from here, late Saturday, officials told IANS.

A team has been constituted to probe the murders. The CBI has also compiled the newspaper clippings and video recordings of the violence, officials said.

"Spade work in the matter has been done. The CBI team will now go to the crime scene to piece together the jigsaw of the three killings and to do some forensic work as well," a CBI official added.

Investigation into four first information reports (FIRs) filed in connection with the killings has been taken over by the CBI.

While two FIRs were lodged in connection with the murder of Nanhe Yadav and Suresh by their family members, two others were lodged by the police and the widow of the slain police officer.

In the FIR lodged by the DSP's widow Parveen, she has accused former state minister Raghuraj Pratap Singh alias Raja Bhaiyya of conspiring to kill her husband.

Officials said that Deputy Inspector General (DIG) of CBI Anurag Garg is likely to visit Balipur Thursday to take stock of the situation and proceed with the investigation.

Following Haq's killing, his widow had demanded a CBI probe into the matter. Chief Minister Akhilesh Yadav not only yielded to her demand, but also asked the CBI to include the murders of village head and his brother into their probe.