FBI Director Comey testifies before House Oversight and Government Reform Committee in Washington. Thomson Reuters FBI experts warn that the bureau is on the "slipperiest of slopes" by reportedly revealing information about an ongoing investigation to President Donald Trump's administration.

And they say it all began with Hillary Clinton's email investigation.

While media accounts and the White House's versions of the story differ, Trump's Chief of Staff Reince Priebus and FBI deputy director Andrew McCabe allegedly discussed an open FBI investigation that members of Trump's presidential campaign had multiple contacts with Russian operatives.

The FBI notoriously doesn't comment on open investigations, and hasn't spoken up about this incident. Longstanding department protocols bar agents from discussing investigations so that the bureau can remain independent from political influence — and experts caution that independence could be at risk.

'The problem is the questions never end'

Democratic presidential nominee Hillary Clinton speaks about the FBI inquiry into her emails during a campaign rally on October 29, 2016. REUTERS

Experts trace the current quagmire back to when FBI Director James Comey sent a letter to Congress 11 days before the election declaring that he was reopening the bureau's investigation into Clinton's use of a private email server while secretary of state. Just three days before Election Day, he sent another letter announcing the FBI had cleared Clinton of any wrongdoing, again.

Timothy Murphy, a former deputy director of the FBI who served under multiple administrations, said the FBI is realizing they shouldn't repeat what they did with the Clinton case, and should revert to their tight-lipped history.

"If you come out one time, even in this rare case, and you talk publicly about an investigation, then I think it gives people — the American public, Congress, the administration — some leverage over you to start saying, 'Well you talked about this investigation, why can't you talk about this next one?" he told Business Insider. "Once you start down that slippery slope about talking about investigations, it puts you into a box, and they've got to get back out of that."

"Once you start down that slippery slope about talking about investigations, it puts you into a box, and they've got to get back out of that."

James Wedick, a retired agent who spent 35 years at the FBI, agreed that the bureau was in "uncharted waters" because of Comey's actions, and said he used to tell his agents to "just say no" when anyone asked them to discuss investigations.

"The problem is the questions never end. It's never just one question. It just begets a whole series of other questions," he told Business Insider. "Today, the bureau is into the argument. Now it's going on forever. And there are more questions. Each time that happens, the public's trust in the bureau becomes undermined. That's why it shouldn't happen. That's where they find themselves today. It's a complicated mess."

Murphy and Wedick both said FBI agents should "keep their heads down," try to ignore the political noise as much as they can, and focus on their jobs to get out of this "box."

Sanford J. Ungar, an FBI historian at Georgetown University, warned that if the bureau tells the Trump administration about open investigations, it could be in danger of being perceived as a puppet investigative agency like ones in some South American or European countries, as opposed to the fiercely independent organization that it has been for decades.

"Once that happens, then there's always going to be suspicion about whether the bureau is going to be used, or is going straight down the middle and investigating the facts," he told Business Insider. "If it appears it belongs to one party, or one administration, or one official within an administration, then it's on the road to perdition."