A traveler from Indonesia has been arrested on felony forgery charges after arriving at Dulles International Airport on Wednesday night with what U.S. Customs and Border Protection officials say were “black money scam” notes.

Tuma Thierry Henry, 50, had arrived at Dulles from Togo when officers discovered $28,500 in fake cash that had been dyed black in his baggage. Henry now faces felony forgery charges.

Lauren Colgan, assistant port director with CBP, says victims are often approached overseas, and offered what they are told is U.S. currency that’s been dyed black so that it can be brought to the U.S. undetected.

For example, said Colgan, the victim is told that they can purchase $50,000 in U.S. currency for $40,000.

“And then what they’ll do is they’ll either sell the victim additional chemicals or coach them how to wash the currency to ‘reveal’ the allegedly authentic currency. And by the time the person realizes they were scammed, that fraudster is in the wind,” Colgan said.

In Henry’s case, CPB officials said that officers scanned the notes under ultraviolet (UV) light and found, “good quality likenesses” of the front and back images of U.S. $100 bills, according to a press release.

Colgan said it’s important for travelers to take extra precaution when approached about money inside of an airport: “Be aware of your surroundings, try to know who you’re talking to. If something sounds too good to be true, it most likely is.”