CBI sources said former Secretary (Security) at the Cabinet Secretariat Sudhir Kumar, former Inspector General SPG N Ramachandran who retired as DGP Meghalaya and former Special Secretary (Acquisition) in the Defence Ministry H C Gupta were examined by the agency as part of its probe.
Kumar was Secretary (Security) during 2004-05, the sources said.
The Secretary (Security) looks after the administration of Special Protection Group (SPG), responsible for closely monitoring the security arrangements of the Prime Minister, former Prime Ministers and members of their immediate families in India and abroad.
A case was registered by CBI against former IAF chief S P Tyagi and 12 others, including his cousins, for alleged cheating, corruption and criminal conspiracy in the helicopter deal in which Rs 360 crore is alleged to have been paid as kickbacks.
The former IAF chief has refuted the allegations against him.
The allegation against the former Air Chief is that he reduced the height of the VVIP helicopters so that AgustaWestland could be included in the bids.
While Narayanan was the National Security Adviser, Wancho had been the head of SPG at the time.
