NEW : $ 6 trillion is more than twice Italy 's national debt . The bonds were discovered as part of an investigation into a local mafia order . The bond was issued in the southern Italian city of Naples . 8 people arrested after $ 6 trillion in fake U.S. bonds found in Italy .
NEW : $ 6 trillion is more than twice Italy 's national debt . The bonds were discovered as part of an investigation into a local mafia group . Arrest order was issued in the southern Italian city of Potenza . 8 people arrested after $ 6 trillion in fake U.S. bonds found in Italy .