Police are warning Hampshire and Isle of Wight residents after a wave of courier fraud cases.
Since October 29, six cases have been reported, with five occurring in the past week, resulting in a total loss of £23,000.
One victim lost £10,000.
This type of fraud involves scammers posing as police officers, bank staff, or internet providers, tricking victims into withdrawing money or handing over bank details.
The fraudster usually collects the money or items directly from the victim's home.
Cases include a man in his 80s losing £3,000 after handing over his card and PIN to a fake bank employee, and a woman in her 80s who was approached by a fake detective constable but lost no money.
A man in his 90s was tricked into transferring £6,000 to a scammer's account, while another woman in her 80s was conned into handing over £4,000.
Detective constable Michael Dumbleton, from the Economic Crime Unit, said: "These fraudsters are heartless individuals who prey on some of the most vulnerable people living in our area.
"Victims of courier fraud can be any age, but are typically in their 70s, 80s and 90s. I urge anyone who has an elderly relative to make them aware of this type of fraud as soon as possible.
"We do not want anyone to fall victim to these scammers and we are taking steps to inform residents of courier fraud; so that they are aware of this type of contact and can avoid becoming a victim.
"If anyone receives a call of this nature, they should not engage with the caller and hang up. We are wholly committed to investigating offences of this nature and will take steps to identify and bring those individuals responsible to justice."
Police are urging people not to engage with these calls and remind residents that genuine officers or bank staff will never ask for personal or financial information over the phone.
Anyone with elderly relatives or friends is encouraged to inform them about this scam.
Victims of fraud are encouraged to report the incidents by calling 101.
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