The I-T department says interest free loans were given to Mr Singh by big builders like DB realty, HDIL and Dinshaw Trapinex Builders.
The department also says that Mr Singh and his son Narendra possessed two PAN cards; the leader, however, claims he did not use the second PAN card and that the earlier one was made after he lost his PAN card in 2005.
There are also allegations that HDIL had lent the space it has leased in Hotel Grand Hyatt for hosting Mr Singh's son Narendra Kumar's engagement. Also, between 2006 and 2010 Kripashankar's son did reveal correct tax according to his income.
In a huge embarrassment for the Congress, Mr Singh quit yesterday after the Bombay High Court asked the Mumbai police to file an FIR against him for "criminal misconduct" under the Prevention of Corruption Act.
"The commissioner of police shall obtain sanction from the government to prosecute Kripashankar Singh for criminal misconduct under the Prevention of Corruption Act," a division bench of Chief Justice Mohit Shah and Justice Roshan Dalvi said.
The bench further said that Commissioner Arup Patnaik shall collect documentary evidence regarding all movable and immovable properties of Mr Singh and his family, including his wife, son and daughter-in-law, who will also be prosecuted for aiding in the crime.
"The immovable properties of Kripashankar shall be attached. We do not want to pass any directions regarding the bank accounts of the respondents as it is alleged that the money might have been washed out," the court said.
The court, while keeping the PIL pending, directed the Commissioner of Police to file a compliance report on April 19.
A prayer by Kripashankar's lawyer seeking a stay on the order was rejected.
In his complaint, Mr Tiwari alleged that Mr Singh had been close to former Jharkhand Chief Minister Madhu Koda, who is currently in jail for alleged involvement in a multi-crore hawala scam.
He alleged that several monetary transactions had taken place between them.
Mr Singh's counsels had opposed the PIL, calling it politically motivated and one that served BJP's interests.
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