The decision to probe the DTH broadcasters was taken after agency sleuths found that some of the telecom companies, under probe in the 2G scam, were also broadcasters of the service, official sources said on Sunday.
The CBI had sought details including the original files containing applications for assigning of spectrum and wireless operating licence for DTH services.
The files pertained to Dish TV India Limited, Reliance Big TV Pvt Limited, Bharti Multi-media Limited, Bharti Business Channel Pvt Limited, Doordarshan, SunDirect TV Pvt Limited and Tata Sky Limited.
CBI sources said it would examine the files as some of these companies were under probe in the 2G scam which included role of former Telecom Minister Dayanidhi Maran in Aircel-Maxis deal.
The CBI is also looking into a possible kickback received by a south India-based TV channel.
In its charge sheet, the CBI has alleged that DMK MP Kanimozhi, daughter of former Tamil Nadu chief minister M. Karunanidhi, had got Kalaignar TV in the Tata Sky bouquet in conspiracy with party colleague and former telecom minister A. Raja.
Reliance Telecommunications has already been charged with criminal conspiracy and cheating in the 2G case. Bharti and Tatas, which are in both DTH and telecom fields, have not been made accused in the 2G scam. Dish TV and Doordarshan are not into telecom business.