Washington (CNN) The FBI rejected a request from White House Chief of Staff Reince Priebus last week to publicly knock down media reports about communications between Donald Trump's associates and Russians during the 2016 presidential campaign, according to multiple US officials briefed on the matter.

The White House denies any inappropriate contact occurred, claims the FBI initiated the conversation and insists Priebus only discussed the news story, not the underlying pending Russia investigation.

The revelation of these conversations raises a decades-old question: Are the White House and FBI permitted to talk about an ongoing criminal investigation?

The ground rules

While no law in the US code prohibits communications between the White House and the Justice Department, guidance issued by the DOJ in 2007 and 2009 explicitly limits communications on pending investigations to avoid any appearance of improper political influence.

"Initial communications between the (Justice) Department and the White House concerning pending or contemplated criminal investigations or cases will involve only the attorney general or the deputy attorney general from the side of the department, and the counsel to the President, the principal deputy counsel to the President, the President, or the vice president from the side of the White House," reads the 2009 memo.

The memos say the communication should only happen when it is "important for the performance of the President's duties and appropriate from a law enforcement perspective."

Former White House counsel and Attorney General Alberto Gonzales under President George W. Bush explained in a CNN interview that "it's very, very important that you limit contacts between the White House and the Department of Justice," for two reasons.

"One, you don't want actual pressure placed upon the Department of Justice in connection with an investigation or prosecution, and two, you don't want the appearance of political influence with respect to an investigation or prosecution," Gonzales said.

New factual details from White House

An administration official said on Friday that FBI Deputy Director Andrew McCabe was the first one to initiate the conversation with Priebus about some of the Russia news reports, and McCabe called some of them inaccurate.

Senior administration officials said Priebus expressed his frustration to McCabe that the administration was "getting crushed" on the story and asked him: "What am I supposed to do?" McCabe initially demurred and then later called Priebus to say the FBI could not comment publicly on the reports.

FBI Director James Comey also called Priebus later to echo McCabe's message -- that he believed the story to be inaccurate -- but said the FBI could not "get into the position of making statements on every story," according to the White House.

The Trump administration defended Priebus' actions Friday, saying he only did what any "normal human being" would have done when confronted with information that a news story is false.

"Someone comes to us regarding any matter and says the narrative, the story that's out there, is not accurate. What sane person would not say, 'Could you please correct this?' ... (T)hat, to me, sounds like the most literally logical sane response that any human being would have," said one administration official.

The White House further insisted on Friday in a briefing with reporters that any discussion regarding the investigation into Russia "didn't occur, it never came up."

Were those conversations inappropriate?

Former officials in the White House and Justice Department say that the propriety of these conversations should be evaluated on three grounds: (1) why was the FBI, and not the attorney general or deputy attorney general, communicating with Priebus on this issue; (2) was the underlying substance of the criminal investigation into Russia ever discussed; and (3) did Priebus pressure the FBI after McCabe and Comey said the agency couldn't refute the news stories publicly?

As to the first issue, one former official from the Obama administration pointed out that DOJ's guidance expressly limits the number of people who can have contact on pending criminal matters.

"It's actually worse (for Priebus) to talk directly to the FBI than to go through DOJ," a former Obama administration official explained. "The FBI is supposed to have another level of independence. ... The public has to believe that the FBI is calling balls and strikes and isn't representing one political party or another."

"It would be unusual for the FBI director or the deputy director to have conversations with White House officials without the presence of the attorney general or deputy attorney general," Gonzales said.

"As the attorney general, I would've felt it more appropriate for the chief of staff to contact me and then I would have a conversation with the director of the FBI," Gonzales added.

Another US official who worked under both Democratic and Republican administrations in law enforcement said from institutional perspective, it was drilled into agents that "all contact between the White House and Justice Department went through a single point of contact -- the Office of the Deputy Attorney General to White House counsel."

No one disputes that did not happen in this case.

Were lines observed?

The thornier question -- whether the underlying substance of any discussions between Priebus and the FBI about an ongoing criminal investigation demonstrates the reality or appearance of improper influence -- may come down to a factual matter.

If Priebus called the FBI directly and tried to influence its investigation in any way, then most former government officials agree that would have been inappropriate.

"Nobody from the White House has any business talking to the FBI about any investigation into Russian influence on the election -- you just don't talk to the FBI about that, full stop," said another former Obama official.

"You really wouldn't touch that with a 10-foot pole," the official said.

But some former White House lawyers say that if the Trump administration's assertion is true -- that the FBI, not Priebus, initiated the original conversation -- then it is disingenuous to expect Priebus to walk away covering his ears.

"The more important question is what happens next," explained one former Obama administration official.

If the conversation ended after Comey said that he couldn't comment on the matter, then that is the end of the story.

"But here's where it could go wrong: if Priebus tries to assert leverage or influence over the investigation, then he's crossed the line," the former official explained.

Gonzales said he would not have a problem with the FBI providing the White House with an update on the status of the investigation (or the White House asking for one), but he too drew a line at discussing the details of the investigation.

"I think the FBI has learned its lesson about talking about an investigation while it's ongoing based upon the investigation of the Hillary Clinton emails," Gonzales said.

Other government ethics experts said that the details of the discussions are what matters and the idea that Priebus only discussed The New York Times story, not the underlying facts of the FBI investigation, seems improbable.

"It's not a line that holds up at all," one former Obama official told CNN. "It's a distinction without a difference, because you can't talk about the story (on alleged constant contact between Trump advisers and Russians known to US intelligence) without getting into the fact that there is ongoing investigation (into Russian influence on the election)."

Harvard Law School professor Laurence H. Tribe said that "the important fact is that the White House and the FBI were improperly discussing an ongoing investigation, particularly one that directly involves the President's inner circle and possibly the President himself, regardless of who initiated the communications at issue."

"(These are the type) of backchannel manipulations the nation learned to avoid after Watergate," Tribe said.