Some of the emails on Clinton's server were reportedly so sensitive that investigators initially didn't have clearance to view them
Reuters
Some of the information that passed through Hillary Clinton's private email server was so sensitive that high-level officials examining the account had to get special security clearance before they could proceed with their probe, NBC's Ken Dilanian reported on Tuesday.
That is according to an intelligence official familiar with the probe into the former secretary of state's "homebrew" server, which is being led by the intelligence community's inspector general, Charles McCullough.
The Federal Bureau of Investigation has also been looking into whether classified material was mishandled during Clinton's tenure at the State Department from 2009 to 2013.
Some of the emails found on Clinton's account — according to a letter McCullough sent to senior lawmakers on January 14 and obtained by Fox News and other publications — contained intelligence so sensitive that it has since been allocated to a special access program (SAP) designation.
SAPs are designed to safeguard information deemed more sensitive than even "top secret."
"The special access program in question was so sensitive that McCullough and some of his aides had to receive clearance to be read in on it before viewing the sworn declaration about the Clinton emails," Dilanian reported.
More than 1,200 emails in Clinton's server contain information that has been retroactively marked "classified" since the investigation began in August. At least two emails contain information that has since been marked "top secret."
On Wednesday, Clinton's presidential campaign spokesman, Brian Fallon, appeared on CNN to dispute the reports. He said the information contained in the emails was not classified at the time it was sent or received by Clinton. He also suggested that that McCullough, the inspector general, has been motivated by partisan politics, calling the leak "very coordinated."
Reuters
Republican lawmakers first asked McCullough to investigate Clinton's server in March 2015. In August, Clinton provided the server to the FBI.
The letter sent by McCullough — who revealed shortly after his probe began in August that two top-secret emails had been found on Clinton's server — was sent days after reports emerged that the FBI was widening its probe into Clinton's emails to determine whether any public-corruption laws were violated during her time at the State Department.
The FBI has reportedly been investigating a possible overlap of the Clinton Foundation charity with State Department business, Fox News reported earlier this month, citing three unidentified intelligence officials.
Clinton, for her part, has insisted that she never violated protocol — noting that she used communication practices that were widespread across the federal government — or passed along material marked classified while she was at State.
Still, she apologized in September for the email arrangement that has remained a headache for her 2016 presidential campaign, in which she remains the Democratic front-runner.