Former Secretary of State Hillary Clinton’s exclusive use a private server and personal email for official government business – a fact first uncovered by the House Select Committee on Benghazi – is a scandal that is not going away.

“[T]here are so many things that have yet to be explained about this whole email issue,” The Washington Post’s Karen Tumulty said yesterday on MSNBC. “What sort of deliberations went on at the State Department? Did someone at the State Department tell her that was okay to do? Who actually sat there and decided which emails would be withheld as personal and destroyed and which were sent [to the State Department]? These are the kinds of things that she really hasn't answered[.]”

There are very serious national security issues at stake. According to Bloomberg’s Eli Lake and Josh Rogin:

The FBI has begun a probe into whether foreign intelligence services compromised Hillary Clinton's e-mail server during and after her tenure as secretary of state, according to U.S. intelligence and Congressional officials.

The damage assessment, which is part of the bureau's investigation into whether the former secretary and her staff mishandled classified information, will hunt for digital traces of cyber-espionage by foreign governments. Even mundane and unclassified Clinton e-mails could provide important insights into the inner workings of the U.S. government and the actions of its top officials.

Clinton herself has dismissed the prospect that her e-mails were hacked. … U.S. officials familiar with the probe tell us the FBI is not so sure. These sources say the damage assessment will be conducted by the FBI's own spy hunters and cyber security experts. … Outside experts assume Clinton's server was hacked.

Asked about Clinton’s actions in May, former Deputy CIA Director Michael Morell said, “foreign intelligence services, the good ones, have everything on any unclassified network that the government uses.”

According to news reports this week, we now know that while she was the president's chief foreign affairs adviser, “Clinton wrote and sent at least six e-mails using her private server that contained what government officials now say is classified information.” We also know that of the Clinton emails released so far by the State Department, 87 threads “include information shared in confidence by foreign government officials, from prime ministers to spy chiefs.” Reuters reported that “this sort of information, whether written or spoken, must be classified from the start, and handled through secure, government-controlled channels.”

These revelations come as the Benghazi Select Committee privately interviews two top Clinton aides, Jake Sullivan and former chief of staff Cheryl Mills. Another key Clinton aide, Bryan Pagliano, has so far refused to answer questions – from anyone, according to Yahoo News’ Michael Isikoff:

The former aide to Hillary Clinton who helped set up and maintain her private email server has declined to talk to the FBI and the State Department inspector general’s office, as well as a congressional committee, invoking his Fifth Amendment right not to incriminate himself ….

Pagliano, who maintained the private email server in the basement of Bill and Hillary Clinton’s home in Chappaqua, N.Y., was first contacted by the State Department inspector general’s office in June, the sources said. …

But Pagliano — a potential key figure in the probe — declined to speak to the inspector general’s investigators, informing them through his Washington lawyer, Mark MacDougall, that he would invoke his Fifth Amendment right, the sources said.

Then, in late July, the State Department inspector general and the inspector general for the director of national intelligence referred the matter to the FBI counterintelligence division to determine if classified information was mishandled through the use of the private email server after finding evidence that classified information was communicated on emails sent through the server. …

At that point, the FBI also sought to question Pagliano and he again refused. …

On Aug. 11, the special committee investigating Benghazi, which first uncovered Clinton’s use of a private email address and server, subpoenaed Pagliano to turn over documents and testify at a hearing on Sept. 10. But this week, MacDougall wrote its chairman, Rep. Trey Gowdy, R-S.C., a letter informing him that his client would not answer questions, citing the fact that the issue “is a subject of investigative activity by the Federal Bureau of Investigation and the Department of Justice.”

As NBC’s Chuck Todd remarked, “when you plead the fifth, as far as the political world is concerned, then you’re already admitting to some potential wrongdoing[.]”

“[B]y pleading the fifth, Pagliano raises the specter of criminal action,” reported CNN’s Elise Labott.

Indeed, there continues to be far more questions than answers these days from Team Clinton.