The agency has already questioned Kanimozhi and former Telecom Minister A Raja in this regard.
Both the DMK leaders and others have been questioned by ED about the alleged transfer of Rs 200 crore to the TV channel, in which Kanimozhi and Sharad Kumar each hold 20 per cent stake.
ED had earlier also scrutinised documents related to the DMK MPs' incomes, properties and personal investments.
It had also initiated attachment proceedings under PMLA against other individuals and certain telecom firms involved in the case.
Besides the cases of Raja and Kanimozhi, a similar probe is underway under the provisions of the anti-money laundering Act against Asif Balwa, Director of Kusegaon Fruits and Vegetables Pvt Ltd, Rajeev Agarwal and Karim Murani of Cineyug Films (Pvt) Ltd.
