Vadra's Skylight Hospitality bought this plot in Kolayat in March 2010.
According to the ED officials, Skylight Hospitality had purchased 69.55 hectares for Rs 72 lakh and then sold it to Allegeny Finlease for Rs 5.15 crore, thus making a profit of Rs 4.43 crore.
In May 2012, it sold off another 29.36 hectares in Kolayat for nearly Rs 2 crore to a French joint venture without adding any value to it.
According to the ED officials, Allegeny bought 69.5 hectares, Sachchiya 17.6 hectares and VCB Trading 53.8 hectares from the three Vadra companies Sky Light Hospitality, Sky Light Realty and Blue Breeze Trading in Bikaner's Kolayat village.
The remaining land was bought by PR Fonroche.
An ED source said the loan which the Bhushan Power and Steel Ltd gave to a company that bought land owned by Skylight Hospitality at seven times higher than the acquisition cost.
The agency had registered a criminal case under the Money Laundering Act in 2015, taking cognizance of the case filed by the Rajasthan police after forgery allegations.
The agency had earlier issued notices to Skylight Hospitality but had not mentioned Robert Vadra's name or any company linked to him in its FIR.
Vadra, along with his 75-year-old mother Maureen Vadra has been questioned by ED for over eight hours on Tuesday.
The agency had earlier issued notices to Skylight Hospitality but had not mentioned Vadra's name or any company linked to him in its FIR.
According to the ED, during investigation it found that Allegeny Finlease as a company was "not involved" in any "real business activities" and many of its shareholders were found to be dummy or non-existent.
The government had cancelled the mutation (transfer of land) of 374.44 hectares of land after allotments were found to have been allegedly made in the names of "illegal private persons".
Revenue officials had said in the complaint that government land in 34 villages of Bikaner that was meant to be used for expanding the Army's firing range was "grabbed" by the land mafia by preparing "forged and fabricated documents" in connivance with government officials.
ED suspects that a huge amount of money was laundered in this case by people buying land at cheaper rates through forged documents.
Last week, Vadra was questioned for over 24 hours for three days -- Wednesday, Thursday and Satrurday in a separate money laundering case.