Two new names, which were not part of the agency's preliminary enquiry, have also been included in the FIR. They include brother of former Union Minister Santosh Bagrodia, Satish Bagrodia and Pratap Aggarwal, Chairman and Managing Director of IDS Infotech respectively.
Tyagi is first Chief of the Indian Air Force to be named in a corruption or criminal case by the CBI.
CBI sources said provisions of Prevention of Corruption Act have also been slapped in the FIR filed by the agency.
The agency has also named four companies--Italy-based Finmeccanica, UK-based AgustaWestland and Chandigarh-based IDS Infotech and Aeromatrix in connection with the case.
Also Read
The sources said suspected European middlemen Carlo Garosa, Christian Michel and Guido Haschkhe, advocate Gautam Khaitan formerly associated with Aeromatric and its CEO Praveen Bakshi, former Finmeccanica Chairman Giuseppe Orsi, former AgustaWestland CEO Bruno SpagnoliniTyagi--Julie, Docsa and Sandeep have also been named in the FIR.
They said the agency has got some documents from Italy and files from the Defence Ministry which indicate criminal conspiracy to make alterations in the requirement of helicopter specifications which suited AgustaWestland.
The agency has also carried out detailed questioning of Tyagi, his cousins--Julie, Docsa and Sandeep, Gautam Khaitan, Praveen Bakshi and Bagrodia--last week, the sources said.
All the accused have denied allegations against them.