Police are warning people to be on their guard against fraudsters following a spate of telephone scams in the Crawley and Horsham area.
In at least two of almost 20 cases victims were tricked into parting with several thousands of pounds.
Money is taken from their bank accounts which they were told had been compromised and handed to couriers or taxi drivers.
One victim was telephoned by a conman claiming to be “Detective Constable Warrant of the Brighton Fraud Squad”.
He was told his bank details had been cloned and advised to withdraw £4,000 and hand it to a taxi driver who would take it to “Scotland Yard”.
The method used by the criminals was typical of scams being tackled by Sussex Police under the name, Operation Edisto.
Fraudsters call their victim claiming to be from either the police or a bank and tell them that their bank details have been compromised and urge them to act swiftly to protect themselves.
They may suggest hanging up and ringing the bank or police back straight away to check the call is genuine.
However, they stay on the line and pretend to be the police or bank and give instructions on how their victim should act to safeguard their money - either withdrawing it as cash or providing their PIN number for the bank to take action.
They then send a taxi or courier, who may know nothing about the crime, to collect either cash or a supposedly compromised bank card.
Detective Constable Rees Hopcraft, of Crawley CID, said: “Under no circumstances would the police or your bank act in this way.
“If you have any suspicions, please do not use the phone you have just been called on to contact the police or your bank. If possible use another phone to report your concerns or to contact a friend or relative to alert them.
“I would urge anyone reading or hearing this message to pass it on to any friends and relatives who may be unaware of this particular type of targeted fraud,
“We want to encourage everyone to continue to resist these callers, who despicably often target elderly and vulnerable people who may easily become confused.”
Anyone who has received similar calls, knows of someone who has or who has other information, is asked to email firstname.lastname@example.org or phone 101, quoting Operation Edisto. Calls can also be made anonymously to the independent charity Crimestoppers on 0800 555111. Or call Action Fraud on 0300 123 2040.