The agency told Special CBI Judge O P Saini that Swamy's prayer to appoint him as a public prosecutor is "not tenable" in law and his private complaint may be dealt separately.
"The said prayer of Swamy to appoint him as special public prosecutor and direct the CBI, the Enforcement Directorate and other prosecuting agencies of the government to assist him in conducting the case is, therefore, not tenable in law and is not worth acceptable," CBI said in its four-page reply.
The investigating agency emphasised that the Centre, as directed by the Supreme Court, has already appointed senior advocate U U Lalit as the special public prosecutor in the 2G spectrum case.
Regarding Swamy's plea that his private complaint should be clubbed with the CBI''s case, the agency said, "Clubbing of both the cases is not in the interest of justice. The complaint of Swamy may be dealt with separately as per the law."
The matter has been put up for further proceedings for May 18 as Swamy told the court that he needed some time to argue on this.
The Janata Party Chief had during the last hearing told the court that he should be associated in the case as he is willing to assist the CBI in a "formal way".
"I have to be associated in a formal way with the CBI's case. I will be happy to assist them. The court should give me a formal status and I do not think CBI would have any problem in this," Swamy had said.
In his complaint, he had made a three-fold prayer which included that his complaint be taken cognisance of and A Raja be summoned to take the case to its logical conclusion.
As per the second prayer, Swamy wanted the court to appoint him "as a deemed public prosecutor under the provisions of the Prevention of Corruption Act."
Swamy also wanted the court's directions to agencies like CBI and Enforcement Directorate to assist him in conducting prosecution and in the further investigation into the scam.