The CBI searched 23 locations in Kolkata and Ranchi including the residential premises of Tapas Kumar Dutta and others, spokesperson R K Gaur said in New Delhi.
The searches were conducted in 18 locations in Kolkata and five in Ranchi after filing an FIR under corruption charges against Mr Dutta and others, he said.
During the searches, the agency recovered Rs 3.5 crore cash and over 5 kg of gold (about Rs 1.4 crore according to current bullion rate) from the residence of Mr Dutta, Mr Gaur said, adding several incriminating documents were also seized.
It is alleged that Mr Dutta during 2016-17 entered into criminal conspiracy with three other officials of the Income Tax department and Kolkata-based businessmen and entry operators, he said.
Text messages sent to Mr Dutta seeking his reaction remained unanswered.
"In pursuance of the conspiracy, Mr Dutta allegedly took huge illegal gratification from the businessmen through a chartered accountant to get the income tax assessment files of different assesses transferred from Kolkata/Hazaribagh to Ranchi," Mr Gaur said.
It was allegedly done to provide undue favours to these tax assessees who were charged with heavy tax liabilities in return for illegal gratification, he said.
Mr Dutta had already issued orders abusing his official position, the spokesperson said.
The CBI recently registered a case against Mr Dutta, Arvind Kumar, Additional Commissioner Income Tax, Income Tax Officer (Tech) Ranjit Kumar Lal, one more Income Tax officer, and chartered accountant Pawan Maurya.
Bishwanath Agarwal, Kolkata-based businessman and director of Anchal Vyapar, private personsSantosh Chaudhary, Santosh Shah, Akash Agarwal, Arvind Agarwal have also been booked in the FIR filed under charges of criminal conspiracy and provisions of Prevention of Corruption Act.