More than 100 people living in south Wales have had money stolen from their accounts after it is thought their bank cards were illegally copied and used.
Up to £1,000 was withdrawn from some bank accounts
It is believed thieves used the information to extract hundreds of pounds from the accounts from across Asia, Britain and America.
Two men have been arrested on suspicion of conspiracy to steal and are on police bail.
Gwent Police said the majority of people affected were from Caerphilly.
Claire Parker from Abertridwr checked her bank account and discovered that her husband's card had been cloned and used 18 times over two days - more than £1,000 was stolen.
The card had only been used by her husband once the previous week to buy petrol.
"I went upstairs and checked online banking and found out that we'd had just under £1,200 missing out of our account," she said.
"So I panicked, phoned the bank and they told me that the card had been used, as little as £6 up to or over £100.
"It's bad and it's upsetting because obviously that's people's well-earned money and you think how can anybody just take people's money off them? They've got no right."
Yal Indram, the proprietor of the Murco petrol station at St Cenydd Road, said there had been many complaints from customers about money going missing from their accounts after using their cards at his service station and he had reported the matter to the police.
He has replaced the chip and pin machine but says he has lost business.
AVOIDING CARD FRAUD
Use one card for restaurants and service station transactions only
Always check your monthly statement very carefully
You can check your credit report free online at annualcreditreport.co.uk/
The National Identity Theft Assistance Centre can tell you what to do to put things right
Source: Credit Reporting Agency
A spokesman for the Gwent force said: "We are carrying out an investigation relating to incidents where people have contacted us stating their accounts have been accessed in various locations throughout Great Britain, America and Asia and money withdrawn.
"The majority of victims have been in the Caerphilly county borough area. In excess of 100 people have been affected.
"People should monitor their accounts and ensure they don't disclose any personal details to anyone else including their bank details."
The amount of money withdrawn varies from £100 to £1000.
Two men from the Caerphilly area have been arrested on suspicion of conspiracy to steal and are on police bail pending further inquiries.
The police have warned people to report any suspicious activity on their bank accounts to the police.
Anyone with any information should contact Gwent police on 01633 838111 or Crimestoppers on 0800 555 111.