Opposition leader Sharad Yadav on Sunday said the Narendra Modi government's only agenda was to defame one family and portray that the country made no progress after independence.
Mr Yadav's remark comes after the ED told a Delhi court hearing the AgustaWestland VVIP chopper case that middleman Christian Michel was misusing legal access by passing chits to his advocates asking them how to tackle questions on Congress leader Sonia Gandhi.
In a statement, Mr Yadav, now a Congress ally, said the Bharatiya Janata Party (BJP) government at the centre was indulging in "cheap politics" and had extradited Christian Michel to divert the people's attention from the Rafale deal and other issues.
Opposition parties have alleged corruption in the purchase of Rafale aircraft from France, a charge rejected by the government.
"I have no hesitation in saying that the ruling party is playing cheap politics by pressuring investigation agencies to name Congress leaders in the alleged misdeed in the AgustaWestland case," Mr Yadav said.
People are not so foolish. They can see through the government's hidden agenda, he added.
Mr Yadav said the Modi government should tell the people what has it done for them since 2014.
Michel, who was extradited from Dubai recently, was arrested by the Enforcement Directorate on December 22 and produced before a special court on Saturday which extended his custody by seven days.
He was earlier in Tihar Jail in the related Central Bureau of Investigation (CBI) case.