New Delhi, Aug 13 (IANS): The BJP Tuesday demanded a Supreme Court-monitored special investigation team (SIT) probe into the purportedly illegal land deals of Congress chief Sonia Gandhi's son-in-law Robert Vadra in neighbouring Haryana.

Bharatiya Janata Party leader Yashwant Sinha said that the central government should take stern steps as the land scam took place in the national capital region (NCR) and also comes under the purview of the income tax department.

"It is not just Haryana, in all of NCR and all Congress ruled states, Vadra has indulged in land grabbing in collusion with the government and administration. When (IAS officer) Ashok Khemka tried to interfere, we all saw what happened to him," Sinha said.

Khemka has alleged a land-licencing scam in Haryana and false documentation in Vadra's land deals in Gurgaon.

Sinha claimed Vadra had a unique business model which involved zero investments and maximum profits.

"He (Vadra) should open a school of management and Finance Minister P. Chidambaram should learn from him how to bring down deficit of India without any investment," he said.

BJP spokesperson Ravi Shankar Prasad said that the party would continue to raise the issue in both the houses of parliament.

"This is a larger issue of corruption. We will raise the issue in Lok Sabha and Rajya Sabha," he told reporters outside the parliament house.