Government Accountability Office investigators testified about undercover operations during which they were able to cross the U.S.-Mexico and U.S.-Canada borders without being stopped for using the same false identification documents that they used three years previously. They cautioned that the birth certificates and drivers' licenses used by 60 percent of individuals crossing these borders are not verifiable and do not adjudicate citizenship. Witnesses also talked about the forensic aspects of identifying fraudulent documents. In the second panel security and electronics experts testified about various technologies being used in state government and private industry that can detect fraudulent documents.