Former telecom minister A Raja, who has so far not cross examined any witness in the 2G case trial, is likely to open his defence next week by questioning his former additional private secretary Aseervatham Achary, a prosecution witness, sources said.

A lawyer associated with Raja's case said he would now start cross examining the witnesses as the CBI has filed the third charge sheet and Achary was a department of telecom (DoT) official.

"Now the third charge sheet has been filed and another reason being that Achary was a DoT official, Raja will now cross examine him (Achary)," the lawyer said.

Raja's counsel, at the commencement of trial on November 11, had told the court that he would not cross examine the witnesses until CBI files its third charge sheet and makes a statement that their probe in the case was complete.

Raja, however, had later said that he would cross examine the witnesses when they would depose on government's telecom policy.

"I will cross examine the witnesses when the policy matter will come. Till date, the witnesses are testifying about Swan Telecom and Reliance Telecom Ltd and I have nothing to do with them," Raja had earlier said.

Achary, a prime witness in the case, was summoned today for his testimony before the court but he was discharged as cross examination of Bharat Amberkar, assistant vice president (accounts and finance), Reliance Infrastructure Ltd, remained inconclusive.

CBI, however, told Special Judge O P Saini that they would examine Achary next after the conclusion of cross examination of Amberkar.

Achary had stated to CBI that DMK MP Kanimozhi, an accused in the 2G case, was the "active brain" behind her party-run Kalaignar TV, which allegedly received Rs 200 crore illegal gratification through a circuitous route from DB Group.

"On being asked, I state that Kanimozhi was also a active brain behind M/s Kalaignar TV who was also widely covered by the Kalaignar Seithigal channel (news channel)....A Raja also used to visit her residence at South Avenue in New Delhi frequently. She is very close to Raja regarding the political work relating to DMK...," Achary had told the CBI.