Christian Michel James, the alleged middleman in politically-sensitive Rs 3,600-crore AgustaWestland chopper deal, was brought to India late on Tuesday night following his extradition by the UAE, the CBI said.
The ruling BJP said the extradition in the case from the UPA era is a diplomatic victory for India and could spell "serious trouble" for the Congress's "first family", referring to Gandhis.
It also asserted that the development was an unequivocal affirmation of the Narendra Modi government's "seriousness in fighting corruption".
Michel landed at the Indira Gandhi International Airport on a Gulfstream jet at 22:35 hours, official sources said.
The operation code-named 'Unicorn' was carried out under the guidance of National Security Advisor Ajit Doval and being coordinated by interim CBI Director M. Nageswar Rao, the CBI spokesperson said.
A team of the agency's officers led by Joint Director Sai Manohar was in Dubai to bring him back, it said.
The agency said that Michel has been brought back to India after completion of the extradition process.
The UAE government had cleared the extradition of 57-year-old Michel after his appeal against the move was turned down by a court there.
His alleged involvement in the chopper deal surfaced in 2012 as a middleman for swinging the deal in favour of AgustaWestland and for making illegal payment of commissions or kickbacks to the Indian authorities, CBI spokesperson Abhishek Dayal said.
Michel was wanted for investigation but he escaped and had avoided joining the probe, he said.
A chargesheet was filed against him in September last year.