The vulnerable woman was exposed to a so-called vishings fraud.
The woman was called by a fake bank official who said she was the victim of an attempted fraud.
The person who pretended to be a bank clerk said that the woman had to transfer money to a secure account.
The police stopped the transfer
The fraud took place in November and this weekend two men and two women were arrested at Kalmar District Court who are now suspected of involvement in the gross fraud.
The fraudsters are said to have defrauded SEK 3.7 million, but the police managed to stop the transfer in time.
The fraud is to be one of the single largest whistling frauds that have been carried out in Sweden so far, the police state in a press release.