CBI sources said a DIG Mahipal Yadav returned today from Milan where the trial against the then executives of Finmeccanica and AgustaWestland are being prosecuted by the Italian authorities for alleged international corruption.
India is being represented as civil party in the case by Defence Ministry.
They said CBI was expecting to get copies of transcripts of phone conversations of middlemen which were intercepted by the Italian agencies but it may take some time because of court's procedural issues.
The sources said a set of over 40,000 documents related to contours of money trail has already been received by the CBI from the Italian court after Defence Ministry became a civil party in the ongoing case in the European country.
The sources said once CBI gets these records it might question Tyagi and other accused again before starting to prepare the charge sheet against the accused.