In total, the investigation found 110 emails in 52 email chains containing information that was classified at the time it was sent or received. Eight chains contained top secret information, the highest level of classification, 36 chains contained secret information, and the remaining eight contained confidential information. Most of these emails, however, did not contain markings clearly delineating their status.
Even so, Clinton and her team still should have known the information was not appropriate for an unclassified system, Comey said.
"There is evidence to support a conclusion that any reasonable person in Secretary Clinton's position or in the position of those with whom she was corresponding about the matters should have known that an unclassified system was no place for that conversation," Comey said of some of the top secret chains.
Throughout this saga, Clinton has said she turned over all work-related emails to the State Department. But Comey said FBI investigators uncovered "several thousand" work-related emails that she had not handed over, and three of those were classified at the time they were sent, though they were not marked as such.