People in the north-east are being asked to be vigilant after reports of counterfeit money circulating.
Between September and December there have been a number of reports of fake £50 notes being used in Aberdeen, Portlethen, Ellon, Fraserburgh, Portsoy, Banff and Elgin.
Investigating officer Detective Sergeant John Lumsden said: “Typically a person has been going into independent retailers and making a small purchase for a few pounds, handing over a £50 note and getting change back. The retailer has later discovered the note is counterfeit.
“We’ve had a number of reports of this occurrence over the last few months and we believe the incidents reported to us so far are all linked.
“Whilst our inquiries are continuing into these incidents I would like to encourage the public and retailers, particularly smaller independent shops, to be on their guard for this type of incident and to call police with any information they have that would help our investigation.
“If retailers are unsure about the authenticity of a note, they always have the option to politely decline and request payment by another method.
“Anyone with information which might assist us with this investigation is asked to contact Police Scotland on 101 quoting reference 3548 of December 5.”