Official sources said Batcha was questioned at the CBI office in New Delhi in connection with the finances relating to his firms and his alleged proximity with the former telecom minister.
Batcha is the promoter of Green House Promoters, a Chennai-based export house, which has come under the scanner of CBI and Enforcement Directorate. The probe agency had conducted searches at his official premises late last year.
Sources said his firms could have acted as a front for possible kickbacks in the scam.
Raja's aide heads several real estate firms and the agencies are trying to find out any money trail in the scam.
Incidentally, Shahid Balwa, managing director of DB Realty, who is currently lodged in Tihar jail has admitted to knowing Batcha for the past few years.