Fake 10,000-colon and 5,000-colon bills are in circulation.
The Fuerza Pública detained a man and a woman in Esparza where they tried to pay for merchandise with fake bills, said police.
The couple had more than 100,000 colons in fake bills in their possession, said police. The couple came from Limón, they said. Esparza is near Puntarenas on the Pacific coast.
The new bills have a number of security features that make it very difficult to fake a good copy.