A year after Reliance Industries Limited (RIL) moved Delhi High Court seeking to quash an FIR registered against them by Anti-Corruption Bureau, the CEO of the same firm on Wednesday was finally questioned by the probe agency.

According to senior officials of the ACB, PMS Prasad, CEO of RIL and two senior officials of the firm were questioned at their Civil Lines office in the Krishna-Godavari Basin case, which was rechristened as the "gas pricing scam" by the current chief minister of New Delhi, Arvind Kejriwal.

Surender Singh Yadav, Joint CP, ACB confirmed the recent development and said, "Mr Prasad, Mr TSL Reddy and Mr Ganguly were questioned and they have told us that RIL will fully cooperate with the investigation".Reddy and Ganguly both are currently the general managers in different departments within RIL.

"The concerned individuals will be called again on May 14 and 15 and if required some other senior officials will be questioned as well," said a senior official of the ACB without delving further into the details of investigation. "At this point all we can say is the questioning has been helpful. This is an ongoing process and we are hoping that the investigation will conclude successfully," the official said.

Earlier this month ACB, had served notices to two oil and gas firms, RIL and its partner Niko Resources Ltd, and called senior officials of the firm to join investigations. Prasad could not appear before the police immediately citing his scheduled trip abroad. However he had later confirmed that he is prepared to be questioned by the ACB on May 13.

This is a clear shift from Reliance industries previous stand in which it had t maintained that it was beyond ACB's jurisdiction to investigate cases against non-Delhi government employees.

Last year in May, Mukesh Ambani owned RIL had moved the Delhi High Court seeking quashing of the FIR registered by the ACB which alleged the firm of colluding politicians and bureaucrats in fixing natural gas prices.The FIR named Reliance Industries Ltd chief Mukesh Ambani, then oil minister Veerappa Moily , former oil minister Murli Deora, and ex-director general (hydrocarbons) V K Sibal as accused.

The FIR stated that the Centre and the RIL had "colluded to double the gas prices" and that the alleged "nexus between RIL and the Cabinet ministers was furthered keeping the upcoming elections in mind".The FIR further stated that the impact of the hike gas prices, "would cost the country a minimum of Rs 54,000 crore every year".

The AAP government will see the recent development as a major success especially after ACB's powers were curtailed by a Central government notification in July last year, within a month of it informing the Delhi High Court that it could investigate the case of corruption against the company and the individuals named in a police complaint.