These robberies are targetting "off the books" employees, many of whom are not legal residents. They get paid in cash, and don't use banks.
The illegals tend to settle in communities together, and it is quite easy to identify them, especially when the work trucks are parked out back at night.
The same thing is happening in the illegal's communities near Atlanta.
As much as I don't like their illegal status, it's a shame that these people who worked hard for the cash are seemingly ignored by the PD. I have little doubt that this gets an ambivalent response at best.
Surprising that it made the front page of the Durham paper though.