Twelve counterfeit $20 bills were used Oct. 8 to make a purchase at Walmart, 131 Eureka Towne Center Drive, in Eureka, Lt. Michael Werges said.
A store employee told police two men left the parking lot in a dark-colored SUV, which was possibly a Chevrolet, the report said.
It was not known how much change the men received when using the fake bills to make their purchase, Werges said.
Werges said Eureka Police were investigating the incident and had not received reports of similar counterfeit money being used at other city businesses. He said anyone with information about the incident should call Eureka Police at 636-938-6600.