They said Karti Chidambaram deposed before the investigating officer (IO) of the case as per the scheduled summons for today.
This was the second time he appeared before the ED in this case after he was first grilled by the agency on January 18.
The central probe agency had earlier summoned Karti Chidambaram on February 2 after which he informed them that he would be unable to depose as he had an interlocutory application pending in the Supreme Court in this case.
It is understood that he today told the IO that he was appearing before the agency "under protest".
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Talking to reporters on January 18, Karti Chidambaram had said that he told the investigators what he had earlier "clearly stated in his petitions in the court" (in the case).
The former Union minister's son was referring to his moving of various courts, including the Madras High Court and the Supreme Court, in response to the ED's action against him.
The central probe agency had registered the case against him and others in May last year.
The ECIR was lodged under the provisions of the Prevention of Money Laundering Act (PMLA).
The sources said the ED was probing the alleged "proceeds of crime" generated in this case.
It was the Enforcement Directorate which had provided information about the alleged illegal payments made by INX Media, based on which the CBI had filed its FIR.
The CBI had also carried out searches at the houses and offices of Karti Chidambaram across four cities for allegedly receiving money from the media firm owned by the Mukerjeas to scuttle a tax probe.
The CBI had filed the FIR against Karti Chidambaram and the Mukerjeas on charges of criminal conspiracy, cheating, receiving illegal gratification, influencing public servants and criminal misconduct.
The agency has alleged that Karti Chidamabaram received money from INX Media for using his influence to manipulate a tax probe against it in a case of violation of Foreign Investment Promotion Board (FIPB) conditions to receive investment from Mauritius.
The CBI has said that it also seized vouchers of Rs 10 lakh which were allegedly paid for the services.
The vouchers were issued in favour of the Advantage Strategic Consulting (P) Limited, a firm "indirectly" owned by Chidambaram's son.
"The FIPB approval was granted in hundreds of cases," the senior Congress leader had said.
The CBI FIR was made out against Karti Chidambaram, his company Chess Management Services, the Mukerjeas (currently in jail on charges of murder of their daughter Sheena Bora), INX Media, Advantage Strategic Consulting Services and its director Padma Vishwanathan.