Central Bureau of Investigation, CBI has started questioning former Air Chief S P Tyagi and his cousins in connection with its ongoing probe into alleged kickbacks in the VVIP helicopter deal.

AIR Correspondent quoting official sources, reports that the agency has already questioned executives of Indian arms of Aeromatrix and IDS Infotech -companies through which alleged bribe was routed from Mauritius and Tunisia in the garb of payments for engineering contracts.

The former Air Chief and his three cousins have denied the allegations.