?Want to upgrade your Visa card to a Gold card? If yes, tell me your date of birth and your card number.?

The city police arrested two persons in Posta on Wednesday for cheating with such an offer. Sandip Ghosh, a credit card marketing agent with a multinational bank, and Abhishekh Gupta, a travel agency owner, were arrested for cheating a security agency owner of Rs 38,000 by offering to upgrade his card.

Police said the duo had duped four others, too. ?The total sum will not be less than Rs 3 lakh to Rs 4 lakh,? said a detective department officer.

?The date of birth and the card number are the key to your card. They also asked for the security number on the reverse,? said Gyanwant Singh, deputy commissioner of police (detective department). ?If these are disclosed to a person, he can do anything ? from online shopping to air ticket booking,? he added.

Singh said Ghosh called Sengupta and asked him if he wanted to upgrade his Visa credit card of a foreign bank to a Gold card. ?Ghosh told him that the credit limit of the new card would be higher and with several other facilities,? said an officer.

Sengupta gave Ghosh his card number and his date of birth. ?Ghosh passed on the information to Gupta,? said deputy commissioner Singh. ?Gupta booked eight air tickets for Rs 38,000 for his clients.?

Sengupta was stunned on receiving his credit card statement. He contacted the bank, but the bank officials said that the tickets were booked against his card and that he would have to pay.

Sengupta lodged a complaint with the detective department. ?We traced one of the passengers and came to know the name of the travel agency on KK Tagore Street, from where he bought his ticket. Gupta said he took cash from the passengers and booked the tickets online from a cyber caf?,? the deputy commissioner said. ?After more probing, Gupta broke down and disclosed Ghosh?s name.?

Sleuths are tracing other crimes that the duo committed in the same style. Ghosh told police of four such instances.