According to a press release on the U.S. Department of Labor’s website:

An investigation by the U.S. Department of Labor’s Wage and Hour Division found Maryland’s Prince George’s County Public Schools system in willful violation of the laws that govern the H-1B temporary foreign worker visa program. Investigators found that PGCPS illegally reduced the wages of 1,044 foreign teachers hired under the H-1B program by requiring the payment of $4,224,146 in fees.

via dol.gov

If anyone knows of other success stories of government investigation into H-1B wage violations, please pass on links and/or information.