The Supreme Court on Monday ordered the disclosure of the identity of the whistleblower to the court before it takes a call on proceedings regarding the controversial visitors’ logbook at CBI director Ranjit Sinha’s Delhi residence.

A bench led by Justice H L Dattu told advocate Prashant Bhushan, who represented the applicant NGO CPIL, that he must first tell the court who leaked the contentious entry register at Sinha’s house.

The court said that it was necessary since CPIL affidavit asking the court to pass orders against Sinha was not in compliance with the SC Rules without disclosing the source of information.

Meanwhile, Sinha’s counsel Vikas Singh disputed the authenticity of the logbook and claimed 90 percent of the entries were fudged.

He alleged that the proceedings targeting the CBI director seemed to be controlled by the Zee Group, whose DNA newspaper had been writing about the way hearing would proceed in court before they actually take place. Singh added that these proceedings were also likely to benefit the 2G cases accused.

The court, which will hear the matter on Monday next, asked Bhushan to disclose whistleblower’s identity in a sealed cover envelope.

On September 8, the court had asked the agency chief to reply to the “very serious” averments against him regarding a visitors? logbook at his Delhi residence, which showed frequent visits by some of the accused in the 2G and coal block cases among others.

It had asked him to file two separate affidavits — one on the merits as to why he should not be removed from the 2G cases besides initiating an inquiry against him, and second, on the maintainability of the application by NGO CPIL, a petitioner in the 2G case, which has sought actions against him in view of damning disclosures by the visitors’ logbook.

Bhushan had handed over in the court the original entry register of Sinha?s residence, claiming two unidentified persons had visited him and gave him the document.