Shannonside Gardai are appealing to people to be aware of the storage details of all their financial data.
Officers in Athlone are investigating the theft of up to 12,000 euro from a woman's bank account where there was no apparent email, internet or phone scam.
The woman had not given her details to any third party.
Gardai say fraudsters have become more sophisticated in their methods and people need to regularly check that their balances are in order.
Sergeant Andrew Harran in Athlone says it doesn't always involve thousands of euro, smaller thefts are also being reported.