The FBI appears to be entering the home stretch of its investigation into Democratic presidential front-runner Hillary ClintonHillary Diane Rodham ClintonDemocrats worry negative images are defining White House Heller won't say if Biden won election Whitmer trailing GOP challenger by 6 points in Michigan governor race: poll MORE’s private email server.
Yet even as arrangements are reportedly being made to interview Clinton and her top aides, much remains unclear.
The FBI under Director James Comey refuses to publicly discuss the investigation, as is customary, but critics say the lingering questions show the review is anything but routine and could result in criminal indictments.
Here’s a look at what is still not publicly known.
When will the investigation end?
The FBI’s investigation had dogged Clinton’s presidential campaign since last summer. The longer it goes, the more likely it is to damage to her chances of winning the Democratic nomination and the White House.
Reports indicate that the bureau is sprinting to complete its work so it won’t be seen as meddling in the presidential election.
Still, according to Clinton, the FBI has yet to reach out to her to schedule an interview, despite reports that she and other top aides could soon be brought in for questioning.
“They haven't,” Clinton said on NBC’s “Meet the Press” this weekend. “But, you know, back in August, we made clear that I'm happy to answer any questions that anybody might have. And I stand by that.”
What law(s) might have been broken?
Top officials at the FBI and Justice Department have refused to discuss what charges — if any — might result from the investigation.
Speculation about the charges has centered on federal statutes prohibiting against removing federal documents, especially 18 U.S.C. § 2071. A portion of that law bars officials from “willfully and unlawfully” concealing, removing or destroying federal records.
Other laws identified by the watchdog group Cause of Action include prohibitions against removing defense-related information “from its proper place of custody” and against removing classified information to keep “at an unauthorized location.”
Critics also say Clinton or her top aides may have violated internal State Department procedures about handling classified information.
Who’s in the crosshairs?
Clinton is the highest-profile name floated as a possible target of the FBI’s probe, but she isn’t alone.
According to Al Jazeera, the FBI is also seeking to interview Clinton’s former chief of staff, Cheryl Mills, and ex-spokesman Philippe Reines. Questions have also mounted about longtime aide Huma Abedin, Under Secretary for Management Patrick Kennedy and former State Department official Jake Sullivan, who authored more emails now considered classified on Clinton’s server than anyone else, according to an analysis by The Washington Post.
A conservative legal watchdog group has asked for eight people to testify in a separate court case relating to Clinton’s server, including Mills, Abedin, Kennedy and IT official Bryan Pagliano. In that case, a federal judge said current and former State Department officials could be questioned about whether the department willfully circumvented the Freedom of Information Act.
Pagliano, who is believed to have been responsible for setting up the server in Clinton’s Chappaqua, N.Y., home, was granted immunity in exchange for his cooperation with the FBI.
What would the government have to prove to file charges?
Perhaps the biggest question for the bureau is whether there was the intent to “willfully” remove government documents, or whether Clinton’s situation was merely an oversight, as she has claimed.
None of the thousands of emails that Clinton handed over to the State Department were marked as classified, the government has said, but classified information can appear in unmarked emails as well.
Upon entering office, Clinton signed a nondisclosure agreement vowing to protect classified information, whether it is “marked or unmarked.”
Last week, the State Department halted its internal probe of whether 22 emails that have been deemed top secret — the highest level of classification — were classified at the time they were sent. The department said it was deferring to the FBI’s investigation.
Former Attorney General Michael Mukasey, who served under President George W. Bush, has said the evidence suggests that Clinton knew at least some of the information was sensitive, and yet kept it on her personal server anyway.
“The simple proposition that everyone is equal before the law suggests that Mrs. Clinton’s state of mind … justifies a criminal charge of one sort or another,” Muksaey wrote in a Wall Street Journal op-ed.
How much will the FBI say?
The Justice Department is in a difficult spot, as it is likely to face a political backlash no matter what it decides in the Clinton case.
Many conservatives already doubt that the Obama administration is willing to pursue an indictment connected to the Democratic presidential front-runner. Lack of formal charges might merely be viewed as proof that the process was not above-board.
Senate Judiciary Committee Chairman Chuck GrassleyChuck GrassleyGrassley announces reelection bid The Hill's Morning Report - Presented by Alibaba - Democrats argue price before policy amid scramble Congress facing shutdown, debt crisis with no plan B MORE (R-Iowa) has pressed for the FBI to release the evidence collected during its investigation once the probe is concluded — regardless of the outcome — to reassure the public that political considerations did not play a role in the Department's decision.
To avoid concerns about impartiality, Grassley and other prominent Republicans have pressed for Attorney General Loretta Lynch to appoint a special independent prosecutor to handle the Clinton investigation.
So far, she has denied the request.
Was the server secure?
Clinton’s camp has refused to outline precisely which digital protections she used to safeguard the information on her private server.
Independent cybersecurity analysts have concluded that the server went at least two months without using standard encryption protections that make data inaccessible to hackers.
Former Defense Secretary Robert Gates in January said “the odds are pretty high” that foreign spies in China, Russia or Iran would have gotten access to Clinton’s data.
Adm. Michael Rogers, the head of the National Security Agency and the U.S. Cyber Command, testified before Congress that, for foreign intelligence agencies, the server “would represent opportunity.”
Will Clinton’s other 30,000 emails ever see the light of day?
Clinton only gave about half of the approximately 60,000 emails she sent while secretary of State to the federal government for record keeping. The rest of the messages, she said, were purely personal in nature and were deleted.
The claim set off a firestorm in Washington, with many Republicans and transparency advocates fretting that Clinton and her team had unilaterally decided to delete half of her email correspondence, without affirming with the government that it was truly personal.
It remains unclear whether those messages can be recovered from the server or if they will ever be released.