In a past life, I was a Database developer supporting the integration of a credit card Fraud Detection System at a large bank. One of the things I was told by the experienced fraud investigators there was about 40% of all credit card fraud related to three categories of large, organized gangs:

• The Bloods and the Crips
• The Asian Fraud Rings
• The Nigerian Fraud Rings

Now, of these three, only the first is "home grown"—the management of the other gangs is foreign. These gangs depend on getting visas or immigration rights to get key people into the US to conduct operations here. The Nigerian Fraud Rings typically excel at "social engineering." The Asian Fraud Rings have the capability to manufacture counterfeit credit cards in factories near Hong Kong and Beijing—and to distribute these cards into the US.

Now, while violent crime and crime against property may be falling in the US, fraud in various forms is on the increase. Credit Card Fraud in the US increased about 35% between 2003 and 2007.

Some kinds of crime do pay—and thus are growing. If we want to understand the real impact of immigrants on crime, we must look at the "growth industries" of the criminal world.