A scammer cheated Northern California Girl Scouts by paying for cookies with counterfeit $100 bills, officials said — as even federal authorities joined the investigation.

Aside from the delicious treats, the scammer is also getting real cash in change from the con.

The grift occurred in three separate incidents last month in Solano, a county between San Francisco and Sacramento, according to ABC 7.

Each time, the scammer gave the Girl Scouts a counterfeit $100 bill for cookies.

The grifter's goal was to receive real cash as change for their purchase, according to Fairfield police.

The first two cons took place in Lowes parking lots, while the third was outside a Peet's Coffee shop, investigators said.

"It's just heartbreaking. These are children, you know? We are taking advantage of our children. In both cases, the person came across as extremely genuine, just wanting to support the Girl Scout troops," said Jennifer Brantley with the Fairfield Police Department.

The Secret Service is also investigating the crime due to the use of counterfeit bills, according to ABC 7.