The government placed its confidential inquiry report in a sealed envelope before a bench of justices G S Singhvi and S J Mukhopadhaya.
The report said that it is difficult to track the source which leaked the tapes which was recorded by the Income Tax department.
"In a nutshell, the report says it is difficult to find by which source it was leaked," the bench said after perusing the report.
The bench further said, "Regarding the source which leaked the tapes, they have been unable to find it."
The bench also said that governemnt has stated in the report that as per the rules all the tapes which were in its possession have now been destroyed after placing the original copy before the apex court.
Advocate Prashant Bhushan, who was appearing for the NGO Centre for Public Interest Litigation (CPIL) seeking disclosure of the entire conversation in the tapes, termed the development as "very surprising".
The second report by the government on its probe into the leakage of the recorded conversation was filed during the hearing of the petition filed by Ratan Tata seeking inquiry into the incident which he alleged was in violation of his fundamental right to privacy.
The government had earlier filed a status report saying that the government agencies were not responsible for its leakage and the Radia tapes broadcast by media organisations were tampered with. It had said that there were eight to ten agencies, including service providers, involved in the tapping.
The conversations were recorded by the government as part of the surveillance ordered by the Directorate General of Income Tax (Investigation) following a complaint received by the Finance Minister on November 16, 2007 alleging that Radia had within a span of nine years built up a business empire worth Rs 300 crore.
The government had recorded 180 days of Radia's conversations -- first from August 20, 2008 onwards for 60 days and then from October 19 for another 60 days. Later on May 11, 2009, her phone was again put on surveillance for another 60 days following a fresh order given on May 8.
