Britons are being urged to be on their guard after a fraudster claiming to be from Amazon swindled two people out of £15,000.
The telephone scam sees victims receive an unsolicited call with a pre-recorded message, where they are invited to connect to an operator to talk about their Prime membership.
After a long conversation, they are then asked to reconnect to the phone call through their computer and download software called Team Viewer, which allows them to share their desktop.
From here, the victim is asked to log into their online bank to check whether they have received a refund from Amazon.
A distraction technique is then deployed to divert their attention away from the screen - enabling the fraudster to quickly transfer funds out of the victim's bank account and even apply for loans.
Avon and Somerset Police said it has recently received reports of three incidents in the area, with two of the victims losing a combined total of almost £15,000.
Avon and Somerset Police warned: "Neither the police nor the banks will ask you for banking details or PIN numbers on the phone. Similarly, they would never send a so-called 'courier' to collect bank cards or money.
"Our message is - don't discuss your finances with anyone who calls you out of the blue, even if they claim to be a police officer or a representative from a bank fraud department or even a well-known company.
"Genuine callers will be happy for you to make an appointment to visit them at a bank branch or police station or for you to call them independently to verify that they have been trying to contact you."
Over a two-month period late last year, Action Fraud said it had received more than 200 reports about similar incidents - with victims losing at least £400,000 to the scam.
Pauline Smith, the head of Action Fraud, said: "Unsolicited requests to remote access your computer should always raise a red flag.
"It's easy to feel embarrassed when faced with unexpected or complex conversations but its okay to stop the discussion if you do not feel in control of it.
"If you've received an unexpected phone call, or other communication, stop and take a minute to think about whether an organisation would get in touch with you out of the blue in this way. Instead, contact them directly using a known email or phone number."
An Amazon spokesperson said: "We take phishing and spoofing attempts on our customers seriously, and will never call a customer for payment outside of our website.
"If a customer has concerns or receives a call they believe is not from Amazon, they can check the Amazon.co.uk help pages for guidance.
"Customers should never provide personal or financial information to unsolicited callers, or ask them to take any actions on their Amazon account," they added.