The CBI has sent notice to former Telecom Minister A Raja to appear before it for questioning in connection with the 2G spectrum scam. The move comes after the CBI raided 34 places in Delhi and Tamil Nadu on December 15 and questioned several persons informally. AIR correspondent quoting official sources reports, similar notices have been sent to others including corporate lobbyist Niira Radia while her close associate and former Chairman of Telecom Regulatory Authority of India Pradip Baijal was being questioned by the CBI sleuths today. Mr Raja, who is in Chennai, was served notice at his official residence to appear before the agency for questioning.More persons will receive similar notices from the agency, which is investigating the 2G spectrum scam. In the just concluded winter session of the Parliament, the CAG report on 2G spectrum scam was tabled. The report has pegged a huge revenue loss to the exchequer .