Police have charged three men over a series of fraud incidents in Aberdeen and Stirling.
Officers say they have received reports in the past fortnight of vulnerable people being targeted by criminals claiming to be from the police or representatives of a bank.
They have allegedly told victims there was suspicious activity on their account, and that a police officer would visit their home to collect their bank card and conduct inquiries, or collect cash withdrawn for safekeeping.
Searches were carried out at properties in Govan, Glasgow and Stirling, leading to the three arrests.
Two men, aged 32 and 56, are due to appear at Stirling Sheriff Court on Monday, and a 27-year-old man is due to appear at Aberdeen Sheriff Court on Tuesday.
A 22-year-old woman was arrested in connection and released pending further inquiries.
Detective Sergeant Scott McKay, of Aberdeen CID, said: "I’d like to thank those who have assisted with our investigation so far. We continue to carry out enquiries and I’d encourage anyone who believes they may have been the victim of a similar fraud to contact police immediately on 101.
"Working alongside our colleagues in Stirling and Glasgow, we’ve shown that no matter where criminals base themselves within the country, they will be pursued relentlessly until they are arrested."
Detective Inspector Davy MacGregor, of Stirling CID, said: "I would remind people that police officers and representatives from banks will never cold call you and ask you to transfer money to another bank account or to withdraw money to be collected for safe keeping.
"Whilst these individuals can appear genuine, if you receive a request like this, please terminate any calls and contact the police immediately on 101.
"I’d also urge those with vulnerable family members or friends to highlight these types of crimes. Working together with communities and other partners, we will disrupt those involved."