REUTERS/Jim Young
U.S. presidential candidate Hillary Clinton listens to remarks at a roundtable campaign event with small businesses in Cedar Falls, Iowa, United States, May 19, 2015.
Two inspectors general have asked the Justice Department to open a criminal investigation into the matter.
The New York Times reports that the request stems from an assessment sent in a memo last month that Clinton's private email account had "hundreds of potentially classified emails" in it.
That assessment conflicts with Clinton's earlier statements that there were no such emails in the private account she used as secretary of state during the first term of the Obama administration.
In a separate investigation by the State Department, it was found that "some information in the messages should be retroactively classified," according to The Times.
The newspaper notes that it is unknown whether or not information contained in the emails was marked classified by the State Departent when Clinton sent or received them.
Since it was first revealed in March that Clinton used a private email account to conduct state business, there have been many questions about whether her actions were lawful, and whether classified government information could have compromised.
In an interview with CNN July 7, Clinton declared there was "no
It is not yet clear if or when the Justice Department would open a criminal investigation.
Broader questions about Clinton's private email server have, at times, drawn attention away from the 2016 Democratic frontrunner's presidential campaign, adding to worries that her use of private email for work-related communication was an attempt to shield the emails from scrutiny under the Freedom of Information Act.
The State Department is currently wading through some 55,000 pages of Clinton's emails as part of its effort to rule out any potential misuse. Three thousand pages of emails were released last month.