But thanks to an alert store clerk, police were able to get a good description of the persons who were passing them, along with a vehicle description and license number.

Greenville Police Chief Duane Alexander said that the clerk, who asked not to be identified publicly, refused to accept one of the bills. When the couple left the store, the employee took down the plate number. "She then saw the vehicle parked in front in a grocery store, and went in and told the manager what happened to her. Apparently, they tried to pass a bill at that location, too, but the store never notified us," said the chief.

Alexander said that once his department completed their end of the investigation, he turned all the information over to the U.S. Secret Service. "Officer (Charlie) Runnells notified the Department of Motor Vehicles once we got a plate number, so we expect to hear back from the feds pretty soon," Alexander said.

The case was turned over to the U.S. Secret Service because Maine doesn't have a counterfeiting statute on the books, the chief explained. "The most we could get them for is negotiating a worthless instrument, a Class D felony, usually good for about a $100 fine. But federal charges carry some pretty stiff penalties," Alexander said.

The chief said businesses need to be alert, especially during busy times of the day. "If you see anything suspicious, call us right away. It's hard to do an investigation after the trail gets cold," Alexander said.