Although Modi announced that India will buy 36 Rafales last year, his Hindu-nationalist government has ordered an investigation into all defence deals initiated under the previous, Congress-led administration, the India Today newspaper reported this week.
Defence Minister Manohar Parrikar confirmed that the 2012 purchase of Pilatus would be investigated, although trainer planes already in service will not be grounded.
He went on to claim that his predecessor, AK Antony, feared that the Rafale talks were being conducted by "a corruption negotiation committee".
"He must have gotten experience with Agusta," he commented, referring to the investigation by Italian prosecutors into allegations of bribe-taking implicating top Congress and state officials in the sale of 12 AgustaWestland helicopters.
The Rafale negotiations began in 2012 but dragged on until the 2014 election - Parrikar has accused Antony of "hammering" the tender so that it would never be accepted - and Modi's government has promised to buy far fewer planes.
Even that deal has yet to be sealed, with the Indian government still trying to beat down the price.
The Indian parliamentary defence committee has complained about the delay.
Whether because of genuine concerns about corruption, attempts to influence the negotiations or domestic Indian political considerations, further delays seem inevitable.