The agency has already questioned executives of Indian arms of Aeromatrix and IDS Infotech -- companies through which alleged bribes were routed from Mauritius and Tunisia in the garb of payments for engineering contracts.
A reference to Khaitan was made in the Italian prosecutor's report filed in a court there. However, Khaitan has refuted all the allegations.
CBI has registered a preliminary enquiry (PE) against 11 persons including former IAF chief SP Tyagi.
Four companies including IDS Infotech and Aeromatrix have been named in the PE.