Beware of fraudsters posing as police officers or bank employees is the message from West Yorkshire Police.
People are being convinced to hand over their bank cards as part of the courier scam, which are then used to withdraw cash.
Around 10 incidents in Leeds and Wakefield are currently being investigated.
Detective Constable Mick Wilson, of the economic crime unit, said: “The fraud works in two parts with the victim initially receiving a call from someone claiming to either work for the police or a bank or building society saying that there has been fraudulent activity or another issue with their account.
“The caller will generally then ask a series of ‘security’ questions, including asking for the PIN number, and then advise that someone will attend shortly to collect the card.
“A taxi driver or courier will then call at the victim’s address and collect the card.
“The police, banks and building societies do not operate in this way and you should not disclose your PIN number to anyone regardless of who they claim to work for. You should also never hand your bank card over in this way. If there is a requirement for you to be issued with a new card then the old card will be left with you to dispose of securely. “
“If you do receive such a call then we would advise not giving any details over the phone and then making enquiries in person at your bank or building society.
Anyone who thinks they may have been a victim should call 101.