The "extremely serious" investigation into Hillary Clinton's use of a private email server while she served as secretary of state is being led by an FBI "A-team," an intelligence source told Fox News.
The source said the investigation is centered around 18 US Code 793, a section of the Espionage Act related to gathering and transmitting national-defense information.
Two emails reportedly found on Clinton's server from 2009 and 2011 contained information regarded as "Top Secret/Sensitive Compartmented Information," one of the highest levels of classification.
