Vikas Kumar, the arrested clerk-cum-storekeeper of Bihar School Examination Board (BSEB), would replace original answer sheets with blank ones for the students who benefited from the Intermediate result scam, said investigators who questioned him.

The Bengal criminal investigation department arrested Vikas, a resident of Patliputra Colony in Patna, from Jinjirabazaar on the southern fringes of Calcutta on Tuesday morning. He was handed over to Bihar police who took him on a three-day transit remand after he was produced in a Calcutta court on Tuesday afternoon. During interrogation, police said, Vikas (39) confessed to providing blank answer sheets to the examinees and their parents.

"I used to charge anything between Rs 5 lakh and Rs 10 lakh each for changing the answer sheets of the examinees who approached me," superintendent of police (Patna central) Chandan Kushwaha quoted Vikas as saying on Wednesday.

The officer said Vikas's mode of operation was simple - he would replace the original answer sheets with new ones after the candidates, aspiring to score excellent marks in the Intermediate examination, filled up the correct answers in connivance with the board officials.

Kushwaha, who is part of the special investigation team (SIT) probing the scam, said on Wednesday that Vikas went about his task innovatively. "He engaged a private firm in Gujarat to supply him the answer sheets," he said, adding that the clerk's role came under the SIT scanner after Ahmedabad businessman Brijlal Kumar lodged a complaint with Kotwali police station recently, alleging he was duped of Rs 8.56 crore by the BSEB storekeeper.

Vikaswent into hiding after he came learnt of the case. "He frequently travelled from one city to another making the job of the police difficult," said an investigating officer. "He was traced to Bengal's Maheshtala Jinjirabazaar from where a joint Bengal CID-Bihar SIT team arrested him."

The SIT has also launched a search for another BSEB staff member, Raj Kishore, who allegedly helped Vikas in facilitating the racket. Vikas will be produced before the special vigilance court in Patna after interrogation, superintendent Kushwaha said.

Investigation revealed that Vikas placed an order with Brijlal's firm, Bindya Enterprises, for supply of answer sheets for the Intermediate examination. The official tender for printing the question papers and answer sheets was given to a printing press in Mathura, Uttar Pradesh.

Bindya Enterprises lost in the bidding but Vikas contacted the proprietor and asked him to supply the answer sheets. "Initially we dispatched 28 truckloads to the BSEB after Vikas Kumar placed the order," police quoted Brijlal as saying. The businessman also said he deposited Rs 4 lakh in Vikas's bank account.

The Gujarat trader suspected foul play once Vikas started avoiding his calls. In addition, he asked Brijlal to dispatch the consignment to a new address. "The consignment was not to be delivered to the BSEB office, which raised suspicion," the SIT quoted Brijlal as telling the cops.

"Once, he facilitated our meeting with then BSEB chairman Lalkeshwar Prasad Singh and secretary Harihar Jha, who suggested that we discuss the matter of supplying the answer sheets with Vikas," Brijlal told the investigating officers, adding that he suspected wrongdoing once he read about the scam in the newspapers.

The members of the SIT were taken aback after they visited Vikas's palatial house in Patliputra Colony. "We have come to know that he has purchased a flat in Calcutta for Rs 80 lakh too," SP Kushwaha said.