Arvind Kejriwal and Prashant Bhushan, India Against Corruption activists who turned politicians recently, have now targeted Congress president Sonia Gandhi's son-in-law Robert Vadra.
They accused Vadra of increasing his wealth from Rs. 50 lakh to Rs. 300 crore in three years by receiving an "unsecured, interest-free loan of Rs. 65 crore" from real estate giant DLF to buy properties at very cheap prices from the same company.
When contacted, an aide of Vadra said he would respond to the charges later.
But Congress leaders and Union ministers quickly came out in support of Vadra, threatening legal action against the IAC.
Rubbishing the charge, Congress spokesperson Manish Tewari said the activists were acting as "BJP's B Team".
The BJP demanded a probe into the alleged deal, but the Congress said such attacks were reminiscent of what its leadership faced in the 1970s and 1980s to defame former prime ministers Indira and Rajiv Gandhi.
Arvind Kejriwal is seen with India Against Corruption colleagues Shanti Bhushan and Prashant Bhushan during a press conference in New Delhi.
Earlier, Kejriwal said DLF could have tied up with Vadra for acquiring land deal on favourable terms through Congress governments in Delhi, Haryana and Rajasthan.
Delhi chief secretary PK Tripathi dubbed the allegation as "factually incorrect and mischievous", saying, "The government was not in the business of allotting land to private entities."
But a DLF spokesperson said, "All our transactions with Robert Vadra are completely transparent and adhere to highest standards of ethics."
Kejriwal said the balance sheets of five companies owned by Vadra and his mother had a total share capital of Rs. 50 lakh in 2007.
"Although they had no legitimate business activity between 2007 and 2010, they acquired properties worth over Rs. 300 crore during the period."
Union ministers Ambika Soni, Salman Khurshid, Rajiv Shukla and Jayanthi Natarajan slammed Kejriwal and his team.
"We will teach him a lesson through legal means," Khurshid said.