The raid at the channel office started a little after midnight and went on till morning. Investigators will soon question Kanimozhi, a Rajya Sabha MP.
The CBI is looking for documents with regard to a Rs. 214 crore transaction that took place between Kalaignar TV and Cineyug Films Private Ltd.
"There was a transaction of R214 crore from M/s Cineyug Films Pvt Ltd to Kalaignar TV in 2009. The funds were arranged by Cineyug from DB Group companies, wherein family members of (Shahid) Balwa are directors or shareholders," the CBI told a special court in Delhi recently.
The pattern of allegations is that after its subsidiary mobile phone firm Swan Telecom got 2G spectrum at low prices, DB Realty sold stake to Etisalat at a profit.
The alleged payment to Kalaignar is seen as a possible quid pro quo. In this, the role of former telecom minister A Raja has become controversial.
Balwa has maintained his company wanted to invest in Kalaignar but the deal didn't take place and Kalaignar returned the money.
Kalaignar TV claims the sum received from Cineyug was an "advance for transaction of shares", and was returned with interest.