Joss paper "hell money" being burnt near a grave along with joss yuanbao burnt at ancestors' graves around the time of the Ghost Festival.
The couple maintains that the bills were merely "hell money."
Hell money is money that is "printed on joss paper and resembles legal tender bank notes but is not legal tender or recognized currency instead, hell money is presented as burnt offerings to the deceased," the CBP release explained.
However, even if the couple did intend to burn the money for ceremonial purposes, "attempting to import any amount of counterfeit currency, regardless of the intended purpose, can have serious implications for arriving travelers," said CBP Port Director Devin Chamberlain in the release.
The couple arrived at the Detroit Metro Airport on February 12, but they offered conflicting stories about how much currency they were carrying.
"A search of their luggage resulted in the discovery of 93 bundles of counterfeit US $100 bills and 32 bundles of counterfeit Vietnamese Dong," the CBP states.
Agents from the Department of Homeland security, and the US Secret Service are now in custody of the bills.
Despite scrape with law enforcement, DetroitNews.com reports that the CBP allowed the couple to continue on in their travels.
However, the CBP statement did not that "the manufacturing of, or importation of counterfeit Federal Reserve notes could result in federal charges."