Clinton aides and department officials stressed this week that the former secretary of state did not violate State policy when she exclusively used a private email account for government work. However, it is currently unclear whether Clinton broke a State guideline dating back to 2005 that suggested "normal day-to-day operations be conducted on an (authorized information system), which has the proper level of security control."
Those guidelines were filled with exemptions that could allow Clinton to use a private account.
The department official was careful to say that the people reviewing the documents are "not going to prejudge the outcome of the review of Secretary Clinton's 55,000 pages of emails."
Clinton was not automatically in violation of State Department policy when she exclusively used a private email during her four years as America's top diplomat, the source added, contradicting other media on Thursday.
"Under federal regulations, there is no prohibition on using a personal email for official business as long as any records are preserved," the official said. "Reports claiming that by using personal email she is automatically in violation of that FAM [Foreign Affairs manual] are inaccurate."
Clinton's use of private email was never hidden from anyone, according to a former State Department official. The former secretary of state sent thousands of employees message from that account and in her four plus years at the State Department, nobody raised a red flag and say that she couldn't conduct her email communication in the manner she was conducting it, the former official adds.
There were no big internal discussion among State Department lawyers, either, about Clinton's use of private email. The former official said it was simply accepted as her form of communication.
Clinton's exclusive use of a private email system has quickly ballooned this week into a controversy for the presumed Democratic frontrunner for president in 2016. Experts have said it doesn't appear Clinton violated federal laws, but that hasn't stemmed the issue that has become more about bad optics and politics.
Clinton tweeted on Wednesday night that she asked State to release her emails.
"I want the public to see my email," her tweet said. "They said they will review them for release as soon as possible."
The State Department acknowledged Clinton's request after the tweet, and a senior official said the review could "take several months."
And while State officials said their review will focus on what can be released, the inquiry will also have to determine what is not suitable for dissemination given its sensitivity. If the department has to withhold documents, questions are likely to be raised about whether Clinton broke State Department guidance for transmuting sensitive but unclassified materials.
On Friday, Marie Harf, a state department spokeswoman, said she was "not going to speculate" about whether there is sensitive information in Clinton's emails.
"We just don't know what would happen in that situation, there are so many variables and factors, I just really don't want to speculate," Harf said.
The New York Times reported on Thursday that Clinton's closest aides at State were well aware that Clinton communicated using a private email address. "Neither career foreign service officers nor State Department lawyers suggested that Mrs. Clinton use a department email address," the Times reported, citing a person with direct knowledge of the inner workings of State Department under Mrs. Clinton.
Clinton's spokesman failed to comment to CNN questions about those revelations by the Times.
A senior State Department official did say on Friday that administration officials who engaged in email exchanges with her would been party to the fact she used a private account, although it is unclear how many administration officials she actually emailed. Several Clinton former senior staffers have said they used to get their instructions from her verbally.
The questions around Clinton's email use have captivated political watchers over the last week and allowed Republicans to cast Clinton in a similar way they did her husband, former President Bill Clinton: As a secretive politician pushing the boundaries and rules and regulations.
Charges of hypocrisy
Charges of hypocrisy have also surfaced given that an inspector general's report from 2012 - while Clinton was secretary - repeatedly cited Ambassador to Kenya Scott Gration's use of "commercial email for official government business"
saying it was against policy to do so "except in emergencies," which created morale problems, "confusion and discouragement within the embassy community." Gration, who resigned his post in 2012 before the IG report became public, was criticized for a number of other things in the document, but it was clear that his using commercial email instead of State Department email was a real concern.
At the time, Clinton was using her own personal email account to conduct official business.
Clinton set up a server at her home in New York to keep her emails, meaning she and her aides were in possession of the documents, not the State Department. When the representatives from State asked for all her records in 2014, Clinton sent them the 55,000 pages of emails. A Clinton aide said they provided "anything that pertained to her work" at State, but it is impossible to verify the former secretary of state did send everything.
State Department guidelines require employees who use private email accounts to back up those documents on government computers so that the department can archive them and they can be available for Freedom of Information Act requests. Clinton aides argue that they complied with State rules when they sent the documents to the department, but that did not happen until 2014, over a year after Clinton left the department.
In addition to directives from State, federal guidelines from Clinton's four years leading the department do not appear to outlaw the exclusive use of personal email devices.
The National Archives and Records Administration, the government agency that regulates the Federal Records Act, issued guidance in 2009 -- the same year Clinton took over at State -- that allowed agency employees to use personal accounts as long as they ensured "that federal records sent or received on such systems are preserved in the appropriate agency recordkeeping system."
Before that, the archives agency said they did not "specifically address this issue."
It wasn't until 2014 - when President Barack Obama signed an update to the Federal Records Law - that a timeline was set up to mandate how quickly emails had to be turned over by people who used personal devices.