The agency had questioned him on various aspects of the case including his alleged links with middlemen, his alleged trips to Italy, reasons behind changing specifications, and relations with his cousins yesterday, the sources said.
Recently, the Milan Court of Appeals in Italy had concluded that bribes were paid to clinch the deal.
CBI had registered a case against Tyagi along with 13 others including his cousins and European middlemen.
The allegation against the former Air Chief was that he reduced flying ceiling of the helicopter from 6,000m to 4,500m (15,000ft) which made Agusta Westland helicopters eligible in the race for the deal.
Tyagi has denied all the allegations against him.
The agency had already questioned Tyagi in 2013 but this session is the first after the Italian court order.
CBI sources said the agency called Gautam Khaitan, former board member of Aeromatrix, one of the suspect in the case, for questioning on Wednesday while cousins of Tyagi--Sanjeev, Rajeev and Sandeep--have been called later this week.
It is alleged by Italian prosecutors that bribes to clinch the deal were paid through middlemen and routed through a consultancy contract between AgustaWestland and companies owned by middlemen.
Khaitan and the Tyagi cousins have strongly refuted the allegations against them.
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