Without naming the officer, CBI sources said an Air Marshal level officer was examined as witness to clarify technical issues related to the tender of 12 helicopters for which UK-based AgustaWestland was chosen as successful bidder.
Sources said the agency wanted to know details of alterations done in the Helicopter specifications and whether it had suited the UK company.
Former IAF Chief S P Tyagi was booked by CBI along with 12 others, including his three cousins for alleged cheating, corruption and criminal conspiracy in the deal and searches were carried out at 14 locations including his the former IAF chief's residence.
It has alleged that Italian middleman Guido Haschke, through his Tunisia-based company Gordian Services Sarl, entered into several consultancy contracts with AgustaWestland from 2004-05 and "almost on back-to-back basis he also made consultancy contracts with the Tyagi brothers (Tyagi's cousins), the sources said.
Under the cover of these contracts, Haschke allegedly sent 1.26 lakh Euros and two lakh Euros to the Tyagi brothers.