CBI sources claimed that some foreign remittances were allegedly received by him in 2009--two years after his retirement--which were the focus of questioning of Tyagi.
They said he was asked about the source of these funds, reasons behind the remittances, and also his travels to Italy after his retirement.
The agency confronted him with account statements and sought to know the explanation.
Refusing to reveal the amount or why CBI has not been able to dig into these details even three years after the registration of the case, the officials said they are looking at these issues with a new perspective after the Milan Court of Appeals order which had concluded that bribes were allegedly paid to clinch the deal.
Tyagi has denied allegations of any corruption in the Helicopter deal.
The agency also questioned today Praveen Bakshi, CEO of Aeromatrix Infosolutions Pvt Limited and Pratap Aggarwal, Managing Director of IDS Infotech who are under scanner for allegedly helping the routing bribe amount from AgustaWestland to various suspected Indian beneficiaries.
They claimed they were questioned about services provided by their companies to AgustaWestland.
CBI had registered a case against S P Tyagi along with 13 others including his cousins, Bakshi, Aggarwal and European middlemen--Guido Haschke, Carlo Gerosa and Chritian Michel.
Tyagi has denied allegations against him and said the change of specifications, which brought AgustaWestland into contention, was a collective decision in which senior officers of Indian Air Force, SPG and other departments were involved.