People in Glossop have been warned about criminals posing as police officers in the town.
Officers say they have received a number of calls from concerned residents who have telephoned them claiming to be from Derbyshire police.
And the fraudsters are targeting the elderly and disabled.
A police spokesman warned: "The call is from someone pretending to be a police officer, who says that he is investigating the unauthorised use of that person’s bank card, advising the person not to tell anyone about this call as it may jeopardise the police investigation.
"If you receive such a call you should not give out any personal information and hang up the call immediately.
"We know that this type of call can be linked to courier fraud.
"This means that victims will be encouraged to withdraw funds from their bank account or give bank cards to a courier, arranged by the ‘police officer’ under the guise of ‘assisting with a police investigation’.
"The police will never contact you asking for banking information or request that you withdraw money from an account to aid an investigation.
"Fraudsters often target geographical areas where they know elderly or vulnerable people live, so if you have family or friends who are vulnerable in anyway that you make them aware of this scam."