The Central Bureau of Investigation searched the house of a former upstream regulator on Friday, the first investigative action after the state auditor said in a report there may have been inflated costs for some of Reliance Industries' exploration activities.
The Comptroller and Auditor General (CAG) said the issue related to the development of Reliance's D6 block in the Krishna Godavari basin, India's largest gas field, causing unquantified losses to the government.
VK Sibal, whose house was being searched, was the chief of the Directorate General of Hydrocarbons, the upstream regulator, when the costs were approved.
"Yes, the raids are on," said an official of the CBI.
"They are in connection with the KG basin case."
Sibal has not so far commented on the case. The oil ministry said on June 13 it would reply to the CAG report within two weeks.