The retired air chief marshal has denied all wrongdoing, but is being investigated along with 11 other individuals by the CBI. Among the group are three cousins of the former air chief who allegedly received kickbacks and Satish Bagrodia, whose brother Santosh belongs to the Congress party and was a minister when the deal was in its final stages of negotiation.
Mr Bagrodia is the chairman of IDS Infotech, one of six companies accused of serving as a conduit for bribes to the former air chief and others. (Read: How bribes may have been routed to India)
The CBI says that the former air chief is being investigated for misusing his official position for the AW deal, signed in 2010, and worth 3,600 crores. The agency alleges that it has found documents that suggest that he changed the Air Force's requirements for the helicopters to match AW's offerings, allowing it to beat two other competitors.
He has pointed out earlier in his defence that the contract was signed three years after he retired.
In statements sent to the Indian government, AW has denied paying bribes to land the deal for the helicopters, intended for the use of VVIPs like the Prime Minister and President.
The inquiry in India came after the ignominy of an Italian investigation disclosing that AW and its parent company, Finmeccanica, had paid bribes worth nearly Rs 350 crores through a complex web of companies and middlemen to land the deal. ('Lots' of evidence against former Air Chief Tyagi: Italian prosecution sources to NDTV)