HIGHLAND, Ill. – Crooks tried to scam one southern Illinois Girl Scout troop. But, they weren’t buying it.

The group was stationed outside of the Highland Walmart when they noticed something was not right.

“This lady came up with a $20 bill to get two boxes of cookies,” said Yumi Hohm, the mother a Girl Scout who was selling cookies. “And she was acting kind of strange, but we run in to a lot of strange people,” she said.

Hohm said she didn’t think much of it until the same woman returned to their table. This time with her boyfriend.

“It really made my heart kind of skip a couple of beats,” said Hohm.

At one point, the group needed change. So, Hohm went inside to the bank.

"I said, ‘Hey, can I get some 20's,’ and the bank lady says ‘Sure,’ and she just looks at it, and she goes, ‘Honey, one of these 20's is fake,’” she said.

There were three $20 bills and they were all completely fake. Highland police said it is pretty rare to catch these criminals in the act. Usually, the fake bills make their way to the bank and by then, the people responsible are long gone.

“Tracking that individual bill back to a transaction to develop a subject is nearly impossible,” said Sgt. Scott Athmer, with the Highland Police Department.

5 On your Side asked Athmer what to look out for when you suspect a fraudulent bill.

“The borders are off on them completely,” Athmer said as he pointed toward several counterfeit bills. Athmer said legitimate bills are printed with green ink and suggested holding the bills up to the light to make sure you can see the security ribbon through the bill.

Hohm said that the experience was a learning lesson for herself and her kids.

"You know, people don’t realize that, when you live in a cute little town like Highland, Illinois you just think it’s so crime free. But, I learned that, it doesn’t matter where you live, crime can happen,” she said.

The couple responsible for handing out the counterfeit bills are now in custody at the Madison County Jail. On Monday, they were identified as Lena Peterson and Christopher Vanbibber. Vanbibber was charged with two counts of forgery while Peterson was charged with one count of forgery and one count of possession of methamphetamine.

They will likely be charged early next week. Police told Five on Your Side that they both have an extensive criminal history.