CBI sources said soon after his arrest last month, Verma had taken names of some influential Congress leaders which included Tytler with whom he claimed to be in regular touch.
They said Tytler was questioned to verify the claims of Verma last month. The sources said Tytler had denied any association with Verma regarding the defence deals.
The Congress leader claimed that his meetings with Verma took place because of his old association with his parents who were also renowned Congress leaders, they said.
Meanwhile, CBI has decided to send judicial requests to United States and Switzerland seeking details of financial transactions of Verma's alleged front company Ganton, based in United States and having subsidiary in India, and Swiss firm Rheinmetall Air Defence AG.
Sources said a team might go to the United States to record the statement of estranged business associate of Verma, US-based attorney C Edmond Allen.
CBI has booked Verma and his wife Ancea Neascu for allegedly taking USD 5.30 lakh from Swiss firm Rheinmetall Air Defence AG for using his "influence" to stall the black-listing proceedings initiated by the government against it after the Ordnance Factory Board scam had surfaced. Both are currently in judicial custody.