Huddersfield has been hit by a wave of counterfeit notes, according to examiner.co.uk.
Hundreds of pounds worth of fake £20 notes are thought to be circulating around the area.
Businesses have been made aware and told to stay alert after several reports came to light of counterfeit money being found in the town in Yorkshire.
Businesses in the Kingsgate Centre and Crosland Moor have both reportedly been receiving counterfeit cash for purchases and police have now stepped in to investigate.
After reports of people trying to pay for items with wads of cash, some of the notes have been seized and are now being analysed by police officers.
Inspector Chris Sheard, of the Huddersfield South Neighbourhood Policing team, PT, said: "We are carrying out enquiries to trace those responsible, but in the meantime we are urging local businesses to take particular care when accepting £20 notes and check that they have all the relevant security features."