Hillary Clinton has a new headache to add to her list: Federal investigators are reportedly working overtime to determine if she lied to the government about her classified email scandal and considering whether to charge her with a cover-up crime that could draw a five-year prison term.

The expanded legal approach could put the former secretary of state in the same boat as TV hostess Martha Stewart, who famously drew a 5-month jail term in a 2004 insider-trading case.

The feds ultimately dropped the main charge against Stewart – that she illegally traded stocks based on inside information – but turned her into a felon for lying to the Securities and Exchange Commission about it.

Clinton also faces a criminal probe related to the federal Espionage Act, whose 'gross negligence' language makes it a crime to move classified national defense documents to unsecure places, even without intending to.

But it could be the cover-up, not the crime, that does her in.

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PRISON STYLE TIPS? Hillary Clinton (left) could be prosecuted under the same lying-to-investigators law that torpedoed Martha Stewart in her 2004 insider trading trial

YOU THINK SHE'S ANGRY NOW? Clinton could go to prison for lying to the FBI – or just for failing to tell President Barack Obama that she was sidestepping security protocols and operating her own private email server when she ran the State Department

'NO': Obama said flatly last month on '60 Minutes' that he wasn't aware Clinton was operating a home-brew email server while she was America's top diplomat

MINIMUM SECURITY, MAXIMUM FLAIR: Stewart served time – not for getting rich on insider trading, but for lying to investigators about it

Her presidential hopes took a hit this year when it emerged that hundreds of classified emails had lived on her home-brew server, outside the reach of the government and its secret-minders.

Now the Department of Justice is working fast and furious to wrap up its inquest early enough in the 2016 presidential campaign season to allow Democrats to replace Hillary as their standard-bearer – if she should find herself too politically wounded to fight on.

COVER-UP STATUTE: THE LETTER OF THE LAW ... from 18 U.S. Code § 1001 - Statements or entries generally [W]hoever, in any matter within the jurisdiction of the executive, legislative, or judicial branch of the Government of the United States, knowingly and willfully – (1) falsifies, conceals, or covers up by any trick, scheme, or device a material fact; (2) makes any materially false, fictitious, or fraudulent statement or representation; or (3) makes or uses any false writing or document knowing the same to contain any materially false, fictitious, or fraudulent statement or entry; shall be fined under this title, imprisoned not more than 5 years or, if the offense involves international or domestic terrorism (as defined in section 2331), imprisoned not more than 8 years, or both. Advertisement

'The agents involved are under a lot of pressure and are busting a**,' an intelligence source told Fox News on Thursday.

Section 1001 of Title 18 of the U.S. Code criminalizes lying or covering up any 'material fact' in a federal investigation, and courts have given prosecutors wide latitude in pursuing charges even when statements are given orally and not under oath.

It's also illegal under the statute to mislead the federal government through a third party by asking –or manipulating – someone to make false statements or engage in a cover-up.

Government officials fold Fox separately that the FBI has decided to perform its own review of the tens of thousands of emails Clinton handed over to the State Deparment a year ago, tossing out other agencies' judgments about what is and isn't classified.

Clinton and her surrogates have suggested that some of the emails deemed 'classified' by the State Department shouldn't have been.

The question of whether any of the material on her private email server was sensitive enough to be considered a significant state secret is an important one.

The federal Espionage Act includes a provision that criminalizes 'gross negligence' by officials charged with safeguarding national defense information.

DEVIL IN THE DETAILS? Clinton may have lied to investigators about her emails, while Stewart was convicted to misleading the government about her insider trading

Separately, the law's text makes a criminal of any security clearance holder who fails to notify his or her 'superior officer' when a breach of security occurs through such negligence.

ESPIONAGE ACT: THE LETTER OF THE LAW ... from 18 U.S. Code § 793 - Gathering, transmitting or losing defense information (f) Whoever, being entrusted with or having lawful possession or control of any document, writing, code book, signal book, sketch, photograph, photographic negative, blueprint, plan, map, model, instrument, appliance, note, or information, relating to the national defense, (1) through gross negligence permits the same to be removed from its proper place of custody or delivered to anyone in violation of his trust, or to be lost, stolen, abstracted, or destroyed, or (2) having knowledge that the same has been illegally removed from its proper place of custody or delivered to anyone in violation of its trust, or lost, or stolen, abstracted, or destroyed, and fails to make prompt report of such loss, theft, abstraction, or destruction to his superior officer — Shall be fined under this title or imprisoned not more than ten years, or both. Advertisement

Hillary could therefore be prosecuted in federal court for failing to tell President Barack Obama about her private email server at the time she was running it.

Obama said flatly during a '60 Minutes' interview last month that 'No,' he did not know Clinton sidestepped security protocols with her a email setup while she was his secretary of state.

A supervisory FBI agent with a 20-year career in federal law enforcement told DailyMail.com at the time that failing to put Obama in the loop could be enough to send her to prison for ten years.

'If investigators conclude that the former secretary [Clinton] was criminally careless in how she approached the security of the sensitive documents in her possession, then this part of the law could be used to prosecute her,' the agent said, on condition of anonymity.

'"Gross negligence" just means "serious carelessness",' he clarified.

His voice became more deliberate and quiet when DailyMail.com asked him to address the notification clause in what is technically known as '18 USC 793.'

'The secretary's superior is the President of the United States,' the FBI agent noted.

'So unless he were aware of what she was doing when she was doing it, it seems there could be a legal problem [for her].'

THE COST OF GROSS NEGLIGENCE? DailyMail.com found that Datto Inc, one of the two companies tasked with managing Clinton's private email server, operates this unsecured server farm with open trash dumpsters near a public road in Pennsylvania

The FBI's investigation of Hillary Clinton's private email server has focused for months on whether she violated the Espionage Act – especially its 'gross negligence' language.

The law applies to 'any document, writing, code book, signal book, sketch, photograph, photographic negative, blueprint, plan, map, model, instrument, appliance, note, or information, relating to the national defense' – even if it's not considered 'classified.'

It calls for a 10-year prison sentence for anyone convicted of 'gross negligence' that permits such information to be 'removed from its proper place.'

Using an unsecured computer network to host sensitive information could qualify, according to the FBI agent who spoke with DailyMail.com in October.

'The only way setting up your own email server for messages about sensitive information isn't negligent is if it's deliberate – which is far worse,' he said.

Clinton has staked her public defense on a repeated claim that she never knowingly sent or received information through her 'clintonemail' domain that was 'marked classified' at the time.