New Delhi: CBI's decision not to book Essar Group and its promoters in a case arising out of 2G case investigations under the Prevention of Corruption Act was on Thursday questioned in the Supreme Court.

An application in this regard filed by the NGO, Centre for Public Interest Litigation, on whose plea the apex court is moniotring the probe in the 2G scam, alleged that "this exclusion has been facilitated by the intervention of Director of Prosecution-CBI and Director-CBI".

"The interference of an influential Minister in the Government, the Law Minister Mr Salman Khurshid, is evident. He is publicly giving clean chit to Essar/Loop," the application said.

"It is to be noted that this case is similar to that of Swan-Reliance wherein CBI has already filed charge-sheets against officials of Swan, Reliance and also the public officials.

The charge sheets include charges under Prevention of Corruption Act. The above developments are likely to weaken the prosecution case in the matter of Swan-Reliance as well," the NGO said.

The NGO filed the application after taking the permission of a bench headed by justice G S Singhvi.

The Essar Group has denied all allegations against them and claimed that the CBI had confirmed that the company was not involved in 2G scam.

It was alleged that the CBI took the decision in this regard despite the investigation officers dealing with the case had found "strong evidence in the case and had apparently/reportedly proposed charges even under the Prevention of Corruption Act".

"Therefore, not charging the accused under the Prevention of Corruption Act ignoring the findings of the Investigating Officers, is unwarranted. This is unacceptable, especially, in a case where the investigations are being monitored by this Court and investigating officers are reporting to the Court.

The agency had on December 12 filed third chargesheet against Essar Group promoters Anshuman and Ravi Ruia, Essar Group director (Strategy and Planning) Vikas Saraf, Loop Telecom promoters Kiran Khaitan and her husband I P Khaitan.

The agency also named three companies-- Loop Telecom Pvt Ltd, Loop Mobile India Ltd and Essar Tele Holding as accused in the case.

All of them have been chargesheeted under section 120 B (criminal conspiracy) and 420 (cheating) of the IPC. Essar Group in a statement had denied all allegations against them.

The NGO also demanded that the agency should probe the role another company Shyam Telelink Ltd, which had got licences, during the tenure of former Telecom Minister A Raja, and in which Russian billionaire Vladimir Yevtushenkov has invested money.

It also accused the CBI for being slow in taking action against DMK MP Dyanidhi Maran in October.

"The CBI filed an FIR on October 9, 2011 and searched the premises of the accused on October 10, 2011.

Since then over two months have passed, the CBI is deliberately going slow in the case and has not made any arrests in the case.

"Petitioners submit that this was the most clear-cut case of corruption and quid pro quo, and is being made weak by the CBI.

Chargesheet should have been filed in this case several months back," the NGO said.