A New Jersey man was shocked when police informed him that the $100 bill he withdrew from his bank to pay taxes earlier this month was a masterfully made counterfeit.

What the man may not have realized is that the State Department has confirmed a rash of these almost undetectable counterfeits, called “supernotes,” have been flooding the U.S. from North Korea in a form of monetary sabotage one former FBI agent warns could constitute an act of war.

The existence of the supernotes was exposed in 2008, when several Chinese men were convicted of smuggling tens of millions of dollars worth of the counterfeit money into the U.S.

Originally, the supernotes fooled even state currency experts.

“It wasn’t until they took [a] bill back to Washington, D.C., and they examined it in the labs of the Secret Service … that they determined that in fact it was a supernote,” author and former FBI agent Bob Hamer explained to the Christian Broadcasting Network. “It’s a near-perfect replica of our $100 bill.”

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But authorities also discovered that the Chinese men hadn’t actually produced the counterfeits; they were only the vehicle for smuggling the currency into the U.S.

Last month, the International Business Times reports, State Department spokesman Philip Crowley confirmed U.S. officials now have “no doubt” that North Korea is behind the counterfeit currency ring.

And that, Hamer told CBN News, could be considered an act of war.

“It’s an act of aggression,” Hamer said, recalling his undercover work that helped expose the counterfeiting plot. “We’re talking about a foreign country counterfeiting our currency and then were going to make me an exclusive distributor of over $40 million of this counterfeit money here in the United States.”

The former FBI agent further explained, “The notes are manufactured in North Korea. They were being distributed through the Russian Embassy in Beijing to the Chinese organized crime figures that were dealing directly with me.”

The ongoing use and spread of the phony money contributed to the State Department decision, announced last month, to initiate a new wave of sanctions against North Korea.

“We have been able to identify sources of revenue, illegal sources of revenue, and we’re going to be working with our international partners to try to stem this flow of illegal activity,” Crowley said.

The U.S. has acted on the crime before, singling out the China-based Banco Delta Asia as an accused conduit for laundering the supernotes. The action led to a freeze of more than $25 million in North Korean assets at the bank; and in 2007, the White House went further, when the U.S. Treasury ordered American banks and companies to sever all ties with BDA.

Still, Hamer told CBN News, he’s surprised the media hasn’t reported more on the financial implications of the phony bills.

“Anytime there’s counterfeit money being circulated in our country its going to have an impact on our economy,” Hamer said, “especially when we’re talking about the dollar amounts that they’re talking.”

As for the man who paid his taxes with the counterfeit $100 bill, New Jersey’s Verona-Cedar Grove Times reports the authorities discovered it by running it through a portable scanner acquired last June to stop a string of phony $20 bills being distributed in Verona.

Police told the paper that the unsuspecting man could be issued a replacement $100 bill once he gets a report from the U.S. Secret Service confirming the original as a counterfeit.

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