More than 100 credit and debit cards may have been stolen from residents in North East Hampshire, according to detectives investigating a major postal scam.
Officers think some people may be unaware they are victims of fraud, thinking their cards have been lost in the post.
It is thought as many as 150 cards may have fallen into the hands of a criminal gang intent on using them to commit fraud, police said.
Surrey Police and Hampshire Constabulary, along with the Royal Mail Security and Investigations Services are now working together on the case.
A police spokesperson said some stolen cards have already been recovered.
A man and woman from Farnham in Surrey and a 23-year-old from Aldershot, who were arrested in connection with the case have been put on police bail pending further inquiries.
Police are urging anyone who has not received a card they ordered in the last five months to contact them.