They were told about the bank accounts in which the money had to be deposited. Eight such bank accounts have been identified so far.

'The money was to be paid in stages to the accused. Some amount was to be paid when the paper was delivered and the rest after the examination if all the questions tallied,' Additional Superintendent of Police Ruchi Srivastava said.

She added that the culprits used to keep the original mark-sheets of the aspirants telling them that if they didn't pay the rest of the money after the examination, they wouldn't get the documents back.

'Of the 12 people arrested, 10 have been remanded to police custody for a week. More names are likely to come up during the course of investigations,' she said.

Chairman of the board M.K. Rai confirmed the cancellation of the exam, saying: 'The exam stands cancelled. There is no decision on the next date.'

Over 21,000 candidates had appeared for the selection test.