People have been advised to be cautious after an incident in which a 90-year-old woman bought a small amount of fish from a cold caller for a large sum.
A man came to the door selling fish, and the pensioner paid for the small amount via a cheque made out for £45, according to Northumbria Police.
However, the cold caller had filled in the cheque details himself, which alerted the woman's family and they contacted the police, who are making inquiries.
The incident happened at a home in Jesmond on Friday.
Officers also want to remind people to be cautious of people calling at the door unannounced, whether they are selling goods or claim to be from a utility company, local authority or even police.
Neighbourhood PC Ben McIntosh said: "Anyone concerned they've been the victim of a bogus caller or are faced with a dubious tradesman, is asked to call police.
"Neighbourhood officers will be in Jesmond over the next few days to offer reassurance and advice to local residents and anyone concerned should not hesitate in speaking to an officer.”
Anyone with information are asked to call police on 101, quoting reference number 565 of 13/0517, or ring the independent charity Crimestoppers on 0800 555 111.