Guernsey Police warn that a number of counterfeit local £10 notes are in circulation.
Police say the notes look like the real Guernsey £10 but don't have the telltale vertical metal strip woven through them.
They all have the same serial number, F068787.
A number of islanders have handed the counterfeit notes in to Guernsey Police over the past week.
Police Constable Peter Geddes is heading up the investigation and he can be contacted on 01481 222222.
Alternatively, anyone with information can contact Crimestoppers anonymously on 0800 555111.

Guernsey Water to take over cesspit collections from States Works
Guernsey Literary Festival to host most events ever
Driver jailed in Guernsey’s first ‘serious injury by dangerous driving’ case
Guernsey Police begin winter roadworthiness campaign
Third mobile provider enters Channel Islands market
Frustration as some struggle to open their Guernsey tax coding notice
Tech-savvy course launches for Guernsey's older generation
8-year-old Guernsey girl wins nature photography award