The agency also said investigation against Essar Group was still on and it will take another two weeks to complete it. CBI, which filed a fresh status report in a sealed cover about the progress of the investigation, said the preliminary inquiry on the alleged involvement of Maran in 2G scam has been completed and letters rogatory (LR) have been dispatched to Mauritius.

"The preliminary inquiry with regard to Maran has been concluded and FIR has to be registered against everyone. A few more days needed for the FIR and can be lodged by month-end," senior advocate K K Venugopal, appearing for CBI, told a bench of justices G S Singhvi and A K Ganguly.

Venugopal said there was delay in filing the third charge sheet in the case as the investigation was still on against Maran and Essar Group for allegedly creating a front company, Loop Telecom, for "illegally" securing the licence for 2G spectrum.

Essar Group has denied allegations of wrongdoing in the scam contending Loop Telecom was not its front company and even had got a clean chit from the Ministry of Corporate Affairs.

Venugopal, who read the portion of the status report about the probe on Maran's role, said CBI has written a letter to a particular company abroad and the follow-up will take place.