The Enforcement Directorate on Thursday raided three locations linked to activist Harsh Mander.
The raids, which began at 8 am, are connected to a money laundering probe based on a FIR (First Information Repot) filed by the Economic Offences Wing of Delhi Police in February this year.
Mr Mander's home (in Vasant Kunj) and his office at the Centre for Equity Studies (in Adchini) were raided simultaneously, as were two children's homes run by his NGO.
The raids were carried out after hours after Mr Mander and his wife had left for Germany; he has taken up a six-month fellowship at the Robert Bosch Academy in Berlin.
Mr Mander's daughter and son-in-law are at the Vasant Kunj home; visuals from the residence show agency officials sitting impassively inside the building while their colleagues carry out searches.
The Delhi Police FIR, filed under instruction from the NCPCR, or National Commission for Protection of Child Rights, has alleged financial irregularities connected to the two children's homes - Umeed Aman Ghar (for boys) and Khushi Rainbow Home (for girls) - in Delhi's Mehrauli.
The Enforcement Directorate - which investigates large-scale financial crimes - is acting on this FIR by Delhi Police, which invoked charges like cheating, breach of trust and criminal conspiracy.
As all three are 'scheduled offences', meaning the agency can take cognisance of the FIR and probe proceeds of the alleged crime linked to the FIR registered by Delhi Police.
Mr Mander had earlier called the allegations "completely unjustified".
"I think it is completely unjustified. We created a very strong system, like we had elder women (caretakers) sleeping with smaller children and we have counselling. It is just an allegation and a rumour," he had said.
The raids have triggered criticism, with senior Congress leader and former Madhya Pradesh Chief Minister Digvijaya Singh calling Mr Mander a "most conscientious and honest officer".
"I have known Harsh Mander since last 40 years as he was a MP cadre IAS official. One of the most conscientious and honest officers I have worked with. Extremely sensitive to the cause of poor (and) underprivileged..." Mr Singh tweeted, saying he "strongly condemned the raids:.
The raids comes as opposition leaders allege that the government is using central investigative agencies - like the Enforcement Directorate or the CBI - to harass and intimidate its critics.
With input from PTI