The FBI is reportedly focusing its investigation into to Former Secretary of State Hillary Clinton’s email scandal on a particular federal law governing “gross negligence” in handling national defense secrets.

As I explained this summer, this felony, 18 U.S.C § 793, could be the most legally problematic for Former Secretary Clinton.

Now, as Fox News reports, that is exactly where the FBI is focusing its key investigation:

Three months after Hillary Clinton’s use of a private email address and server while secretary of state was referred to the FBI, an intelligence source familiar with the investigation tells Fox News that the team is now focused on whether there were violations of an Espionage Act subsection pertaining to "gross negligence" in the safekeeping of national defense information.

Under 18 USC 793 subsection F, the information does not have to be classified to count as a violation. The intelligence source, who spoke on the condition of anonymity citing the sensitivity of the ongoing probe, said the subsection requires the "lawful possession" of national defense information by a security clearance holder who "through gross negligence," such as the use of an unsecure computer network, permits the material to be removed or abstracted from its proper, secure location. . . .

The source said investigators are also focused on possible obstruction of justice. "If someone knows there is an ongoing investigation and takes action to impede an investigation, for example destruction of documents or threatening of witnesses, that could be a separate charge but still remain under a single case," the source said. Currently, the ongoing investigation is led by the Washington Field Office of the FBI.

This criminal provision is clearly implicated by the facts that have been coming out about Former Secretary Clinton’s use of a private unsecured email server.  As I detailed in August:

Secretary of State Clinton had “possession” of “Top Secret” information, which according to federal regulations (18 C.F.R. 3a.11) means it was “national security information or material which . . . its unauthorized disclosure could reasonably be expected to cause exceptionally grave damage to the national security.”

18 U.S.C § 793(f) governs the “possession” of “photograph, photographic negative, blueprint, plan, map . . . relating to the national defense.”  The “Top Secret” “national security information” on then-Secretary of State Clinton’s private email server reportedly contained spy satellite imagery.

18 U.S.C § 793(f)(1) makes it a federal felony for anyone in possession of this type of national defense photos, maps, etc. who “through gross negligence permits the same to be removed from its proper place of custody . . . .”  Secretary of State Clinton knowingly and intentionally had an unsecured, private email server set up at her home and used that unsecured, private email server to conduct some of the most national security intensive business possible as Secretary of State (Benghazi, Iraq withdrawal, early stages of the Iran deal, and on and on).  She chose to “remove” that classified information – or should have known the high likelihood that she would receive this kind of information as Secretary of State – from the State Department’s secure email server to her own private, unsecured home-brew email server . . . stored not within the highly secured confounds of the State Department, but in her house hundreds of miles away in Chappaqua, New York.

Former Secretary of State Clinton’s excuse that the emails may have not been marked classified at the time is irrelevant.  In fact, the standard here is simply “gross negligence.”  Should a U.S. Secretary of State know better than to remove critical national security related information (which a Secretary of State is bound to be privy to) from its proper secured server and place it on a personal, home-brew, unsecured email server in her private residence?

The more we learn, the worse this situation gets.  The White House is (rightfully) walking back President Obama’s recent assertion that “I don’t think it [Clinton’s unsecured email and server] posed a national security problem.”  The White House was quick to clarify that the investigation needed to continue and that his comment was “certainly was not an attempt, in any way, to undermine the importance or independence of the ongoing FBI investigation.”

It’s critical that this investigation continue.  Over 80,000 people have signed our petition at the ACLJ calling for a full, not faux, investigation into the ongoing scandal.  We’ve also put together a thorough legal analysis of many of the federal laws implicated by the facts we know so far. It’s time the American people learned the truth.

Matthew Clark is Senior Counsel for Digital Advocacy with the ACLJ. Follow Matthew Clark: @_MatthewClark.