An 87-year-old man in the Borders has been conned by callers alleging he was the subject of an arrest warrant.
They phoned him on Friday and again on Saturday claiming to represent HM Revenue and Customs.
They told the elderly man that the warrant would be cancelled if he bought £500 in iTunes gift cards at Tesco.
Their victim bought the cards and gave them the serial numbers. But when they asked for a further £1,300 in vouchers, he became suspicious and hung up.
In a second attempted scam, a woman received a letter saying she might be entitled to an inheritance which had lain dormant for some time in Asia.
The letter was on plain white paper and only provided a contact telephone number in Malaysia and a personal Gmail address.
'Elderly and vulnerable'
PC Kirsty Neish said: "Unfortunately a lot of scams are directed at the elderly and vulnerable in our community and processes that immediately raise suspicions to some are not as obvious to others.
"Payment by iTunes vouchers or contact details such as a Gmail address may not raise suspicions if you don't know what they are.
"In all circumstances if you have any suspicions at all, end the call."
She advised members of the public to wait at least five minutes and if possible use another phone before trying to contact any company back.
"Never use the number provided. Always use the number you would usually use to contact the company," she added.
"Never give any personal details out on the phone."
An HMRC spokesperson said it took security "extremely seriously".
"We are aware that some people have received telephone calls from individuals claiming to be from HMRC," he said.
"We have a well-known brand, which criminals abuse to add credibility to their scams.
"We recommend that if you cannot verify the identity of a caller that you do not speak to them."
He encouraged people to visit gov.uk for information on how to avoid and report scams, recognise genuine HMRC contacts and make payments to HMRC.