The CBI sent summons to former telecom minister A Raja and corporate lobbyist Niira Radia on Monday, asking them to appear for questioning in the 2G-spectrum scam.
It is learnt that Radia could be questioned any time while Raja will have to appear later this week. The Enforcement Directorate has already questioned Radia.
Raja (47), who is at present in Chennai, visited Apollo hospital for a check-up immediately after getting the notice on Monday, raising the speculation that he might get admitted to hospital to evade questioning.
But he said, "I am not afraid of the CBI. I am a lawyer. I will abide by the law. I will not evade the law."
Earlier on Monday, Raja had a meeting with his mentor, Tamil Nadu chief minister and DMK patriarch M Karunanidhi.
Sources in the agency said on condition of anonymity that the CBI would compare Raja and Radia's answers and might arrest them if these did not match.
The Supreme Court has asked for the CBI report by February 10 when the matter comes up for hearing.
On Monday, the CBI grilled former TRAI chairman Pradeep Baijaln for about three and a half hours in Delhi.
Raja was forced to resign on November 14 for his alleged role in the scam. Radia is being probed for lobbying for telecom firms.