Hillary Clinton’s email problems are already causing headaches for her presidential campaign. But within American counterintelligence circles, there’s a mounting sense that the former secretary of state may not be the only Obama administration official in trouble. This is a scandal that has the potential to spread to the White House, as well.

The Federal Bureau of Investigation can be expected to be tight-lipped, especially because this highly sensitive case is being handled by counterintelligence experts from Bureau headquarters a few blocks down Pennsylvania Avenue from the White House, not by the FBI’s Washington Field Office. That will ensure this investigation gets the needed “big picture” view, since even senior FBI agents at any given field office may only have a partial look at complex counterintelligence cases.

And this most certainly is a counterintelligence matter. There’s a widely held belief among American counterspies that foreign intelligence agencies had to be reading the emails on Hillary’s private server, particularly since it was wholly unencrypted for months. “I’d fire my staff if they weren’t getting all this,” explained one veteran Department of Defense counterintelligence official, adding: “I’d hate to be the guy in Moscow or Beijing right now who had to explain why they didn’t have all of Hillary’s email.” Given the widespread hacking that has plagued the State Department, the Pentagon, and even the White House during Obama’s presidency, senior counterintelligence officials are assuming the worst about what the Russians and Chinese know.

EmailGate has barely touched the White House directly, although it’s clear that some senior administration officials beyond the State Department were aware of Hillary’s unorthodox email and server habits, given how widely some of the emails from Clinton and her staff were forwarded around the Beltway. Obama’s inner circle may not be off-limits to the FBI for long, however, particularly since the slipshod security practices of certain senior White House officials have been a topic of discussion in the Intelligence Community for years.

Hillary Clinton was far from the only senior Obama appointee to play fast and loose with classified materials, according to Intelligence Community insiders. While most counterspies agree that Hillary’s practices—especially using her own server and having her staffers place classified information into unclassified emails, in violation of federal law—were especially egregious, any broad-brush investigation into security matters are likely to turn up other suspects, they maintain.

“The whole administration is filled with people who can’t shoot straight when it comes to classified,” an Intelligence Community official explained to me this week. Three U.S. officials suggested that Susan Rice, the National Security Adviser, might be at particular risk if a classified information probe goes wide. But it should be noted that Rice has made all sorts of enemies on the security establishment for her prickly demeanor, use of coarse language, and strategic missteps.

However, Clinton should take no comfort from the fact that others may be in trouble with the FBI too. Just how many of her “unclassified” emails were actually classified is a matter of dispute that will take months for the FBI to resolve with assistance from the State Department and Intelligence Community. The current figure bandied about, that something like 300 of the emails scanned to date by investigators contained information that should have been marked as classified, is somewhat notional at this point, not least because the Intelligence Community has yet to weigh in on most of them.

Spy agencies typically take a harder line on classification than the State Department does, including a tendency to retroactively mark as classified mundane things—for instance, press reports that comment on security matters can be deemed secret—that other, less secrecy-prone agencies might not. That said, there’s little doubt that our intelligence agencies fear that the compromise engendered by Hillary’s email slipshod practices was significant.

Although it will be months before intelligence agencies have reviewed all Clinton emails, counterintelligence officials expect that the true number of classified emails on Hillary’s servers is at least many hundreds and perhaps thousands, based on the samplings seen to date.

Excuses that most of the classified emails examined to date are considered Confidential, which is the lowest level, cut no ice with many insiders. Although the compromise of information at that level is less damaging than the loss of Secret—or worse Top Secret—information, it is still a crime that’s taken seriously by counterintelligence professionals. Most of the classified emails that Hillary and her staff seem to have compromised dealt with diplomatic discussions, which is a grave indiscretion as far as diplomats worldwide are concerned.

“Of course they knew what they were doing, it’s a clear as day from the emails,” opined one senior official who is close to the investigation. “I’m a Democrat and this makes me sick. They were fully aware of what they were up to, and the Bureau knows it.” That Hillary and her staff at Foggy Bottom were wittingly involved in a scheme to place classified information into ostensibly unclassified emails to reside on Clinton’s personal, private server is the belief of every investigator and counterintelligence official I’ve spoken with recently, and all were at pains to maintain that this misconduct was felonious.

It’s clear that many people inside the State Department had to be aware, at least to some degree, of what Clinton and her inner staff were engaged in. How far that knowledge went is a key question that the FBI is examining. The name Patrick Kennedy pops up frequently. A controversial character, Kennedy is the State Department’s undersecretary for management (hence his Foggy Bottom nickname “M”). A longtime Clinton protégé, Kennedy is believed by many to be the key to this case, since his sign-off likely would have been needed for some of Clinton’s unorthodox arrangements.

Described by more than one insider as “the State Department’s J. Edgar Hoover,” Kennedy is a figure of mystery to many. “I’d put talking to him near the top of my list,” explained a retired senior FBI official, a career counterintelligence agent. “Would Kennedy go down for Hillary? Maybe,” he added, “But will some GS [General Schedule] or FSO [Foreign Service Officer],” meaning a career State Department employee, “go down for Hillary? I doubt it. The FBI will get someone to talk, we always do.”

Where the FBI’s investigation of EmailGate is headed is anybody’s guess. The Clintons do have a long history of hanging tough and outlasting scandals. Obama’s Department of Justice may be able to quash prosecutions, no matter what the FBI finds. But it cannot stifle Congress. And more than one committee is interested in Hillary’s emails, far beyond the Benghazi investigation. Congressional investigators are looking into issues beyond classification, to include possible dirty financial deals orchestrated by Hillary when she was at Foggy Bottom, to benefit her husband and the Clinton Foundation.

“This was about a lot more than just some classified emails,” a senior Capitol Hill staffer told me, “and we’ll get to the bottom of it. But we’re happy to let the FBI do the heavy lifting for right now.” Although many on Capitol Hill are frustrated by a lack of information sharing by the White House about EmailGate, and many other matters, “This is different,” the staffer opined, “now the media won’t let go—and the Bureau definitely won’t. I wouldn’t want to be Hillary right now.”

Another cause for concern is the rising number of questions emanating from even generally pro-Clinton media outlets. Now that The Washington Post has reported that Hillary indeed both sent and received classified information on her personal account—despite her protestations that she did no such thing—this is not a scandal that sufficient incantations of Vast Right Wing Conspiracies can make disappear. While Clinton loyalists may defend Hillary to the end, that may be cold comfort given what any rigorous investigation of EmailGate might turn up.