The U.S. Secret Service is examining more than $100 billion of U.S. government bonds confiscated in northern Italy in August, just two months after $134 billion of allegedly fake securities were seized in a nearby town.

The Secret Service is analyzing whether the bonds taken in August may be counterfeit, said a spokeswoman for the U.S. embassy in Rome. Italy’s financial police in Varese, north of Milan, arrested two individuals carrying the securities in a briefcase, according to a person involved in the case.

The two men currently are in custody as prosecutors in the town of Busto Arsizio carry out their investigation, the person said. The seized notes include securities with face values of $500 million and $1 billion, Italian daily MF reported today, without saying where it got the information.

“There must be a well-organized group behind these alleged crimes,” Fabio Polimeni, a Milan lawyer specializing in counterfeiting cases, said.

Italian authorities seized U.S. treasuries on June 4 with a face value of more than $134 billion from two Japanese travelers attempting to cross into Switzerland. The two men later disappeared and the case is still under investigation. The U.S. government bonds found in the false bottom of a suitcase carried by the men were fake, a U.S. Treasury spokesman said June 18.