One summer afternoon, two "Japanese" men in their 50s on a slow train from Italy to Switzerland said they had nothing to declare at the frontier point of Chiasso. But in a false bottom of one of their suitcases, Italian customs officers and ministry of finance police discovered a staggering $134bn in US Treasury bills.

Whether the men are really Japanese, as their passports declare, is not entirely clear, but Italian and US secret services working together soon concluded that the bills and accompanying bank documents were most probably counterfeit, the latest han-diwork of the Italian Mafia.