Counterfeit bills popping up in McNairy Co.

Authorities in McNairy County are warning businesses to beware of funny money.

Police say several counterfeit $20 bills have already turned up and more may be out there.

The problem surfaced when a McNairy County resident tried to make a purchase unknowingly using a bogus bill at a Wal-Mart.

For more information on what to do with counterfeit bills, you can contact the FBI .