A public warning has been issued over counterfeit Bank of Ireland £50 notes being spent across Scotland.
Police said they were mainly being used in Dumfries and Galloway, the Borders, Stirling and Tayside.
Det Insp Iain McPhail said suspects were using both an old style green £50 note and a newer purple one.
Businesses have been advised to decline to accept any green notes while purple ones should be "robustly examined" to establish their authenticity.
"If anyone is presented with a green old-style £50 note they should be declined and the customer informed to take them to their local bank," said Det Insp McPhail.
"All genuine new style purple sterling notes feature a watermark, a hologram that changes, a series of dashes which become a solid line when held up to light and has the name of the bank in raised print.
"Each note has an individual serial number."
Anyone who suspects they have been given a fake note has been advised to decline it and consider contacting the police.