The Congress is a partner of the JMM-led ruling alliance in the state.
The Income-tax department has detected "unaccounted" transactions and investments worth more than Rs 100 crore after it raided two Jharkhand Congress MLAs, their alleged associates and linked coal and iron ore businesses across the state last week.
The CBDT said in a statement on Tuesday that 50 premises in Ranchi, Godda, Bermo, Dumka, Jamshedpur and Chaibasa in Jharkhand, Patna (Bihar), Gurugram (Haryana), and Kolkata (West Bengal) were covered during the searches launched on November 4.
The two MLAs, on the day the searches were initiated, were identified by the officials as Kumar Jaimangal alias Anup Singh and Pradip Yadav.
Mr Jaimangal, a legislator from Bermo seat, also spoke to reporters outside his Ranchi residence that day confirming the action, saying he was extending all cooperation to the raiding teams.
Mr Yadav, who joined the Congress after splitting from the JVM-P, represents Poriyahat assembly seat.
The Congress is a partner of the JMM-led ruling alliance in the state led by Chief Minister Hemant Soren.
The CBDT statement said the action was taken against "few business groups engaged in coal trading/transportation, execution of civil contracts, extraction of iron ore and production of sponge iron.
"Those searched include two politically exposed persons and their associates," it said.
The Central Board of Direct Taxes (CBDT) is the policy-making body for the I-T department.
It said cash worth more than Rs 2 crore has been seized and "unaccounted transactions/investments exceeding Rs 100 crore were detected so far." The searches also led to the seizure of large number of "incriminating" documents and digital evidences,it said.
"A preliminary analysis of these evidences indicates that these groups have resorted to various modus-operandi of tax evasion including inflation of expenses, transactions of loans in cash, payments/receipts in cash and suppression of production. "It has been found that investments have been made in immovable properties, the source of which could not be fully explained," the CBDT alleged.
It was found that one of the groups engaged in civil contracts was "not" maintaining regular books of account, it said.
"The group has been inflating its expenses by entering into non-genuine transactions of purchase of raw material/sub-contract expenses in lumpsum at the fag end of the year. "Evidences seized also suggest that unfair payments in cash have been made to secure contracts," the CBDT claimed.
In the case of the other group engaged in coal trading/extraction of iron ore etc, "unaccounted" stock of iron ore of huge value has been found, which is yet be quantified, the statement said.
"The said group has also introduced its unaccounted money in the form of unsecured loans and share capital by layering the transactions through shell companies. "Professionals associated with this group have admitted that they had not verified any supporting documents and had signed the audit report prepared by the group's accountant without due diligence," the CBDT alleged.
Mr Jaimangal, in August, lodged a police complaint against three MLAs of his party -- Irfan Ansari, Rajesh Kachchap and Naman Bixal Kongari-- alleging that they were plotting to topple the ruling UPA government in Jharkhand led by Chief Minister Hemant Soren.
The complaint was filed after the three Congress MLAs were arrested with cash in West Bengal in July.
State Congress spokesperson Rajiv Ranjan had alleged on the day of the searches that the tax department action was part of an operation to destabilise governments in non-BJP ruled states.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)