The BJP on Tuesday accused Lalu Prasad and his family members of involvement in a "soil purchase scam" - a contract worth Rs 90 lakh for earth filling work in the Sanjay Gandhi Biological Park which the party says has been awarded without due process being followed and smacks of conflict of interest.

Senior BJP leader Sushil Kumar Modi said Lalu Prasad's minister-son Tej Pratap Yadav had given the contract of Rs 90 lakh to the park - described as Patna's lungs - which is spread over an area of 153 acres. Tej Pratap's forest department, which has jurisdiction over the park, gave away the contract to a company without following the tender process for construction of a pathway and beautification work, Modi alleged.

Lalu Prasad scoffed at the allegations. "The charges levelled against me and my family are baseless. What is happening in the zoo should be asked from its director. I am ready to face any investigation. If any of my family members or I have received any money there should be a record. On the other hand, for the last 18 months I have been providing cow dung (used as fertiliser) to the park free of cost," the RJD chief said.

Modi, the former deputy chief minister, said the soil dumped was sourced from a site located near Saguna Mor where the construction of a mall touted as Bihar's biggest is on. Modi said the land on which the mall is being built is registered in the name of Delight Marketing Company Pvt Ltd, whose initial director was Sarala Gupta, wife of Lalu confidant Prem Gupta, a Rajya Sabha member.

The company, set up in 1981 and whose address is shown as D-1088 New Friends Colony, New Delhi, had on June 26, 2014, incorporated as directors Tej Pratap Yadav, Tejashwi Yadav - Lalu's two sons and ministers - and Chanda Yadav, the third daughter of the RJD boss. "

The CM should probe the whole episode," Modi said and demanded the ouster of Tej Pratap if the investigation found him guilty.

The mall is being constructed by Meridian Construction India Limited, a firm owned by RJD MLA from Sursand (Sitamarhi), Syed Abu Dojana. "The soil being dumped in Sanjay Gandhi Biological Park came from the excavation as the mall is to have a two-level underground parking slot. First there should be a probe if the biological park needed a pathway, which looks more like an embankment. Second, the biological park is under the ministry of forest and environment which is headed by Tej Pratap Yadav. If payment has been made, then there is a conflict of interest. Also it needs to be probed if a Rs 90-lakh contract can be given without calling for a tender," Modi said.

Dojana said Modi was "lying" when he accused the RJD leaders of using soil from the under-construction mall to build the park pathways. "I am a builder. Whoever provides me the land I will start construction work. Even if the land belongs to Sushil Kumar Modi or Prime Minister Narendra Modi," Dojana told The Telegraph.

He expressed ignorance over soil excavated from the site being sold to the biological park and said he himself was facing a shortage of soil. "Modiji is telling lies and I will file a defamation case against him," the MLA said.

Modi recalled that in 2008, Rajiv Ranjan Singh a.k.a Lallan Singh, the present water resources minister and the then JDU state president, had alleged that Lalu, as railway minister, had handed over two railway hotels in Ranchi (Jharkhand) and Puri (Odisha) to hotelier Harsh Kochar. Lallan had alleged that in lieu of the transfer of the railway hotels, Lalu had been given two acres of land which was transferred to Delight Marketing Company Pvt Ltd. "I challenge Lallan to deny his own statement," Modi said.

Sanjay Gandhi Biological Park director Nand Kishore dismissed Modi's charges. "The total sum being paid for the soil is half of what is being mentioned. I made my own enquiry and the soil is not from the mall. We are using soil to make a pathway in the biological section where there are no animals," he said.

JDU spokesperson Sanjay Singh accused Modi of trying to spread canards. "Modiji has gone into political coma and is desperately trying to revive himself," Singh alleged.