The agency is probing Kanimozhi and others on the basis of FIR filed by the CBI in connection with the alleged channelling of Rs. 200 crore to DMK family-run Kalaignar TV through a circuitous route.
The ED had summoned her and others for questioning about the alleged transfer of Rs. 200 crore to the TV channel, in which she and Kalaignar TV MD Sharad Kumar hold 20 per cent stake each.
Some other transactions are also under ED's scanner in the 2G scam.
The ED, according to the sources, had earlier scrutinised documents related to the DMK MP's income, properties and personal investments and plans to take the probe forward, they said.
The ED had earlier initiated attachment proceedings under the Prevention of Money Laundering Act (PMLA) against other individuals and certain telecom firms involved in the case.
Besides the cases of Raja and Kanimozhi, similar probe is underway under the provisions of the anti-money laundering Act against Swan Telecom promoter Shahid Usman Balwa's cousin Asif Balwa, Director of Kusegaon Fruits and Vegetables Pvt Ltd Rajeev Agarwal and Karim Murani of Cineyug Films (Pvt) Ltd.