Bharatiya Janata Party (BJP) leader Ravi Shankar Prasad targeted Sonia Gandhi and her son and Congress vice president Rahul Gandhi over the land deals.
He said they should explain the "Robert Vadra model of development" when "there is so much unemployment and economy was down".
Prasad told a press conference here the BJP was not targeting an individual. "It is a text book case of corruption, crony capitalism under patronage," he said.
Terming Vadra as "damad shri", Prasad said land acquisitions by Vadra's firms had flouted several laws, including the Land Acquisition Act in Congress-ruled Haryana and in Rajasthan where the party was earlier in power.
"Vadra's land deals have the blessings of Sonia Gandhi and her son Rahul Gandhi," he said.
"Both Sonia Gandhi and Rahul Gandhi should explain Vadra's land deals which generated huge profits for him," he added.
The BJP released a video and a booklet on Vadra's land deals. The video made repeated attacks at Vadra and said the people will not forgive the Congress in the Lok Sabha election.
The video said while there were cases of "bhai bhatijavad (nepotism)", Vadra had added a new tradition of "damadvad (son-in-law favouritism)".
"Damad (son-in-law) should prosper even if farmer is destroyed," said a slogan in the video.
BJP sources said the booklet will be distributed in different parts of the country.
"He (Vadra) made huge profit of Rs.300 crore in a few years from an intitial investment of Rs.1 lakh," Prasad said.
"If an investigation is carried out, there will be criminal cases in Vadra's name," he said.
Prasad's attack Sunday came amid concerted offensive by the Congress on BJP's prime ministerial candidate Narendra Modi over his Gujarat model of development. Apart from Sonia Gandhi and Rahul Gandhi, Priyanka Gandhi Vadra has been hitting out at Modi.
The BJP attack came two days ahead of the April 30 polling for 89 Lok Sabha seats in seven states and two union territories.
Balloting for all 26 seats in Gujarat will also be held April 30. Modi is contesting from Vadodara in the state.
Prasad said the Haryana government accorded speedy clearances to Vadra's firm regarding land use.
Answering queries, Prasad said Rajasthan's BJP government was looking into the allegations concerning Vadra's land deals.
"Nothing will be done out of vendatta. Law will take its own course," he said.
Prasad also asked why Vadra did not go for land acquisitions outside Rajasthan and Haryana in non-Congress ruled states.