A racket in siphoning off tax-payers? money from the civic treasury accounts was unearthed on Monday at the treasury department of the Gariahat office of the Calcutta Municipal Corporation (CMC).

An FIR was lodged with the Gariahat police station by Biplab Roy, treasurer of the office.

Initial estimates revealed that Rs 65 lakh (2004-05) has already been siphoned off by computer operators working in the treasury department by deleting the entry of the deposited tax amount.

However, CMC and police probing the case said the scam could run into crores. At the CMC?s Gariahat office, over Rs 70-80 lakh are deposited every day in taxes. ?We are not sure how long the racket has been going on,? said an official.

About two weeks ago, CMC officials got a whiff of the racket when some tax-payers came back with inflated receipts against tax paid at the Gariahat branch. ?We were stunned to find that the bills were original, but the entries were not accurate. The assessment department, which decides the amount to be paid, carried out investigations in coordination with senior treasury officials,? he said.

The treasury department found out that money was taken by treasury officials as deposits but were not correctly entered in the computer.

Later, the computer operators cracked the password and deleted all the entries. ?So when the details were sought, the investigators drew a blank,? an official explained.

Mayor Subrata Mukherjee was informed about the fraud on Monday. ?Some computer operators have been indulging in deliberate undervaluation of properties. We will take action against them,? he said.

The incident follows similar scams unearthed in several city hospitals, where officials were found guilty of accepting money against receipts without making official entries.