Quotes of the Day

Let's call it the Great Euro Escapade.

About a week ago, German police launched dawn raids on the homes and offices of six people, four of them Chinese, in and around Frankfurt, as authorities closed a net around conspirators in one of the boldest and strangest bank jobs ever.

According to German prosecutors, between 2007 and 2010, a ring of Chinese gangsters and flight attendants from the German airline Lufthansa carried out a €6 million ($8.5 million) coin fraud. The gang is accused of reassembling 29 tons of scrapped euro coins sold to the Chinese as scrap metal, then carrying the coins back to Germany and exchanging them for new ones at the Bundesbank, Germany's central bank.

The scam was discovered a year ago when one of the flight attendants, the only woman in the alleged ring, attracted the attention of border guards at a German airport as she struggled with her heavy luggage. A customs official searched her bag and found thousands of one- and two-euro coins, sparking a year-long investigation that culminated in the arrests on March 30.

It is believed to be the biggest euro fraud in history. The plot was ingenious, and the flight attendants played a central role. The first step, say prosecutors, was for members of the Chinese gang, posing as scrap-metal dealers, to buy a bunch of old euro coins. Before putting coins on the scrap-metal market, European central banks render them worthless as currency. The Bundesbank, for example, stamps deep grooves into the coins. It is not clear where the coins in the German case came from, but it is unlikely that they originated from Bundesbank stocks. The fraud ring made use of the way the coins are made. The two-euro coin consists of a brass-and-nickel alloy center surrounded by a nickel and copper ring. The one-euro coin has a copper-and-nickel center surrounded by a nickel-and-brass ring. Subcontractor firms charged with destroying the coins punched out the core, leaving the coins in two parts. The gangsters' business plan was to put the two pieces back together and redeem the damaged coins for new money at the Bundesbank.

The Bundesbank is the only institution that exchanges damaged euro coins for new ones free of charge. The central bank requires only that people put the coins in a special bag — available over the Internet — that can hold up to €1,000 worth of coins. Bundesbank workers then do spot checks, but according to prosecutors, the Chinese gang mixed counterfeit coins with real coins, making it harder to detect the fakes.

After that, the question was how to transport the heavy coins from China to Germany to trade the counterfeits for real money. That is where the flight attendants came in, the prosecutors say. The Chinese coin gang allegedly made use of one of the perks bestowed upon flight attendants: no weight limits on personal luggage. And that, say the prosecutors, is how Lufthansa flight attendants came to dutifully cart more than 29 tons of counterfeit coins all the way from China to Germany.

The stewardess whose luggage tipped off police last year told Frankfurt prosecutors that she was unaware of doing anything wrong, saying Chinese friends had asked her to trade the coins in Germany because local banks would not accept coins, according to the Hong Kong newspaper Sing Tao. The stewardess was not arrested because she had not redeemed any of the coins. The six suspects arrested in the case are not talking, German prosecutors say.

Unless they start talking, the authorities may never figure out how far or wide the coin caper reached. In one of the buildings raided near Frankfurt last week, police found a coin-assembly machine and more than three tons of coin pieces allegedly waiting to be reassembled and cashed in. They also found computers and about €1 million ($1.4 million) in cash. It is not clear how many of the alleged conspirators were Lufthansa employees or whether employees of other airlines were also involved. A Lufthansa spokesman said only that the airline is aware that several of its employees are under investigation. The prosecutor said in a statement that no Bundesbank employees are suspected of wrongdoing in connection with the coin caper.

As the investigation continues, one thing is certain. In the future, German travelers will probably think twice before asking a flight attendant if they can help her with her heavy bags.

• William Boston / Berlin
• According to German prosecutors, a Chinese gang worked with Lufthansa flight attendants to steal millions from Germany's central bank by rebuilding old euro coins to trade in for new