The GAO created a fake company and were able to gain membership to multiple Internet platforms giving them access to vendors selling military-grade electronic parts. The GAO requested quotes from numerous vendors asking for 16parts which were 1)authentic part numbers for obselete and rare parts, 2) authentic part numbers with post production date codes, 3) bogus or fake part numbers that are not associated with any authentic parts.
The parts were sent to a third party test house. The testing concluded that all parts were either suspect or bogus parts. "Each part failed mulitple component analyses, including visual, chemical, X-ray, and microscopic testing" (pg.8).
All test reports, photos, and more information regarding this investigation can be found in this document released by the US Government Accountability Office.