Official sources said the summons to Tyagi have been issued under the provisions of the Prevention of Money Laundering Act (PMLA).
While the exact date when Tyagi is supposed to appear before the Investigating Officer (IO) of the case here has been kept under wraps, it is understood he has been asked to come "in person" in the next week.
CBI has questioned Tyagi earlier in the same case and he had then denied any wrongdoing.
Sources indicated Tyagi's questioning is necessary in the light of a recent judgement of a Milan (Italy) court which had sentenced Italian defence and aerospace major Finmeccanica's former chief Giuseppe Orsi and the former CEO of the firm Bruno Spagnolini on corruption charges in the sale of a dozen AgustaWestland helicopters to India for VVIP purposes.
The allegation against the former Air chief is that he allegedly reduced the height of the VVIP helicopters so that AgustaWestland could be included in the bids.
He took over as the Indian Air Force chief on December 31, 2005 and retired from service in 2007.
ED had registered a PMLA case in this regard in 2014 and named 21 people including Tyagi in its money laundering FIR.
It had also arrested Delhi-based businessman Gautam Khaitan and had also filed a charge sheet last year.
ED is probing the case in which 70 million Euros (about Rs 360 crore) were allegedly paid as kickbacks.
The agency had earlier submitted that Khaitan was on the board of Chandigarh-based company Aeromatrix which was allegedly a front firm for the financial dealings in the chopper deal.
On January 1, 2014, India scrapped the contract with Finmeccanica's British subsidiary AgustaWestland for supplying 12 AW101 VVIP choppers to the Indian Air Force (IAF) over alleged breach of contractual obligations and charges of paying kickbacks to the tune of Rs 423 crore by it for securing the deal.
In view of the corruption charges, India has also barred Finmeccanica and its group companies from participating in any new programme of the defence ministry.
The central agency has also issued Letters Rogatory (judicial requests) to ten countries in this case.
Business Standard has always strived hard to provide up-to-date information and commentary on developments that are of interest to you and have wider political and economic implications for the country and the world. Your encouragement and constant feedback on how to improve our offering have only made our resolve and commitment to these ideals stronger. Even during these difficult times arising out of Covid-19, we continue to remain committed to keeping you informed and updated with credible news, authoritative views and incisive commentary on topical issues of relevance.
We, however, have a request.
As we battle the economic impact of the pandemic, we need your support even more, so that we can continue to offer you more quality content. Our subscription model has seen an encouraging response from many of you, who have subscribed to our online content. More subscription to our online content can only help us achieve the goals of offering you even better and more relevant content. We believe in free, fair and credible journalism. Your support through more subscriptions can help us practise the journalism to which we are committed.
Support quality journalism and subscribe to Business Standard.