Police in Dubuque are now investigating the latest in more than 100 cases of counterfeit money this year.
Lieutenant Joe Messerich says store employees in Dubuque are getting good at spotting fake currency, but it's not so easy for people who don't handle money all the time.
"That could be people selling on a secondary marketplace like Facebook or Craigslist, sometime landlords collect cash rent - you know just kind of the every-day public that doesn't usually work behind a register that's taking cash for payment, sometimes they're getting duped by these big bills."
Dubuque police have investigated 123 cases involving counterfeit currency this year, in denominations from 5 to 100 dollars.
The latest case is a 100 dollar bill. He says it's a more obvious fake than some others found in the city this year.
"Obviously, characters from a foreign language would be a big red flag considering it's US currency. But a lot of time "feel" will give it away - the bill just doesn't feel like other money would feel."
He blames high quality printers, and websites selling fake bills, for making counterfeiting an increasing problem for law enforcement locally and nationwide.
His advice includes don't be in a hurry to accept payment from someone, and if you are going to, then meet them at their bank and watch them withdraw the money. Good information is also available from the Secret Service and the website US currency dot gov (uscurrency.gov).