The deal to buy the "bunker buster" rifles was concluded when the previous Bharatiya Janata Party (BJP)-led government was in office.

The case was registered under sections of the Prevention of Corruption Act relating to receiving illegal gratification and causing loss to the government exchequer, along with certain sections of the Indian Penal Code.

The CBI had in April sent a letter to the defence ministry in which it said that in order to conduct a probe, it needed a specific complaint for the investigation along with a notification so that the agency could examine and find out whether a case could be made out.

The documents subsequently handed over to the CBI by the defence ministry included a file pertaining to the purchase of the anti-material rifles, on which former defence minister George Fernandes had raised some queries and later approved the contract.

The allegation of payment of commissions by Denel to a British agent to secure the Indian contract for arms and ammunition had triggered a major political controversy in India.

South African newspaper "Cape Argus" had earlier reported that Denel had paid British company Varsa to help it secure Indian price negotiation committee documents relating to the deal.

The newspaper had also claimed that South Africa's elite anti-corruption bureau was probing the pay-offs allegedly made by Denel.

It was on the basis of these allegations that the Indian government ordered a probe and put on hold all deals with Denel till the completion of the investigation.

Denel was providing technology to set up an ordinance factory at Nalanda in Bihar, Fernandes' parliamentary constituency.