"What most people don't know is that the cookie sales are a cookie program," said Girl Scout Central California South CEO Cathy Ferguson.
It's a program where girls learn how to set goals, budget their money and work as a team to help others in need.
"We have over 5,000 girls that can't afford to be Girl Scouts and because of this cookie program they are able to have Girl Scout program," added Ferguson. "So I take it very personally when someone tries to pass off an illegal bill to a little girl. I think that's something one of the lowest things anybody could do as an adult."
But on Saturday someone scammed the scouts.
"I think that's sad, the girls are trying to raise money for community service projects, for camping trips and I think that's sad that someone would want to take advantage of them," said troop leader Debbie Kemmer.
Sometime in the afternoon hours Ferguson said a woman described as African-American, in her thirties and riding a black 10-speed bicycle, handed the cashier at the Girl Scout store on West Shaw Avenue a fake $100 bill. Then on Sunday, she said a woman matching that same description tried to buy three boxes of caramel delights from a booth on the northeast side - using more of the same counterfeit cash.
"Fortunately, because the leader had some training on it, she looked at the $100 bill and saw that it was a $5 bill that was imprinted with a $100 bill over the top of it and she could see it through the light," said Ferguson.
Luckily the mom didn't accept the cash and an alert was sent out to other parents warning them of the scam, but one troop we talked with isn't taking any chances - going one step further to protect their scouts' honor and keep their cookies safe from the crooks.
"When in question, we can always use our credit card swipe this year. This is a fantastic device. It hooks on to a smart phone and then we're all clear and we see instantly when a transaction is approved," said Kemmer.
Both incidents were reported to Fresno Police and the department said the United States Secret Service is investigating the counterfeit cash.
In the meantime, the Girl Scouts said the woman may have an accomplice. They're also on the lookout for an Hispanic male around the same age.