MARTIN COUNTY, Ky. (WSAZ) -- Deputies in Martin County are looking for a woman who spent more than $100 in counterfeit bills at one store.

The counterfeit bills were used at the Save-A-Lot in Inez, Ky. and deputies say they were convincing.

"There's a little bit of a difference in coloring, but they're almost the same as what a real bill is," said Martin County Deputy Bryan Tipton.

Employees at that Save-A-Lot say they quickly noticed something was not quite right.

"She had reached our cashier the money and stuff and she actually was going to count it for the cashier which our cashiers always have to recount the money anyhow," said Save-A-Lot Office Manager Elizabeth Fitch.

When the cashier counted the $20 bills she thought the paper quality was not the same, and, in standard procedure, she marked them with a counterfeit pen.

Employees called police, but the woman got away.

Employees and police agree the best way to tell the difference in real and counterfeit money is to mark it with a counterfeit pen. They say it shows up black or dark brown on regular paper and yellow on real money. The ink on those bills showed up too dark to be real money.

Deputies are asking anyone with information to call the Martin County Sheriff's Office.