The Central Bureau of Investigation on Friday filed a chargesheet before the special court in the murder of Kunda DSP Zia-ul Haq without naming former minister Raja Bhaiya, who was an accused in the FIR filed by the officer's wife.

CBI sources, however, clarified that probe into the alleged role of Raja Bhaiya is still open and the agency might file a supplementary chargesheet if his role surfaces at a later stage.

They said CBI has mentioned in the chargesheet that brother of village head Nanhe Yadav, who was shot dead before Haq, was killed by gun shot from his own weapon in a scuffle which took place after the arrival of police at the crime scene.

The sources said CBI has booked Babloo Yadav, son of Nanhe, his two brothers among others for allegedly killing the DSP.

On Thursday, the agency had moved an application in the court of special CBI judge Mirza Zeenat seeking permission to conduct polygraph test on the former food and civil supplies minister with his consent.

The court has fixed June 11 as the next date of hearing on the application.

Haq was shot dead on March 2 in Balipur village in Kunda area of Pratapgarh district where he had gone to probe murder of village head Nanhe Yadav.

Haq's wife Parveen Azad had accused Raja Bhaiya of conspiracy after which he had to resign from the Cabinet on March 4