On Jan. 24, 2017, then-national security adviser Michael Flynn was questioned by the FBI in his White House office. The session, focusing on Flynn's transition talks with the Russian ambassador, led to Flynn pleading guilty to a charge of lying to investigators. He is now awaiting sentencing.

But why did FBI agents go to the White House in the first place? We still don't know precisely, because we have only snippets of information from the various Trump-Russia investigations. There's no reason it should be a big secret, but it is.

Newly-unredacted portions of the House Intelligence Committee Republican Trump-Russia report say top Justice Department and FBI officials — Sally Yates, James Comey, Andrew McCabe, and Mary McCord — gave "conflicting testimony" about the "primary purpose" for sending the FBI to question Flynn.

Some said the reason for interviewing Flynn was "investigating potentially misleading statements to the vice president," according to the report. Some said it was investigating "a possible violation of the Logan Act." And some said it was "a desire to obtain more information as part of the counterintelligence investigation" into Flynn.

Who said what? It's impossible to know, because the committee has not released the interviews it conducted with each of those players in the Flynn affair. And we're lucky to know what little we know; the intelligence community originally blacked out the portion of the report that said Yates et al gave conflicting accounts. Even that was a secret until the last few days.

Beyond the specific issue of the Flynn questioning, the Republican report's little snippets of quotations and characterizations of testimony leave much untold. They also leave many wondering whether the GOP told the whole story of what its investigators gathered.

In their minority report, House Intelligence Committee Democrats included a few passages from interviews with key figures — former Office of National Intelligence chief James Clapper on his contacts with the press, McCabe on the Logan Act, and more. But of course, the brief passages are just the ones Democrats want the public to see. Like Republicans, they leave a lot out.

The bottom line is that the public still does not know what many important players have told the House about the Trump-Russia affair.

The solution is obvious and simple: release the transcripts of the committee's witness interviews. Among others, the committee questioned Donald Trump Jr., Jared Kushner, Michael Cohen, Corey Lewandowski, Steve Bannon, Rick Gates, Hope Hicks, Sam Clovis, Stephen Miller, K.T. McFarland, Roger Stone, Jeff Sessions, Carter Page, Erik Prince, J.D. Gordon, Reince Priebus, and Sean Spicer. It would be a public service — actually, it is a public responsibility — for the committee to release those interviews.

A good example is about to be set by the Senate Judiciary Committee. One of the areas that panel has focused on is the much-discussed June 9, 2016, meeting in Trump Tower. Committee investigators questioned six of the participants, including Trump Jr., music promoter Rob Goldstone, and the translator who heard it all. (The committee received written answers to questions from Natalia Veselnitskaya, the Russian lawyer at the center of the meeting.) The transcripts of those interviews remain secret.

"[The Trump Tower] section section of our investigation is done," Judiciary Committee Chairman Chuck Grassley announced in January. "So, now it's time to start officially releasing the transcripts of all witness interviews we have done related to that meeting." Grassley said that four months ago, and it has taken all this time to get committee Democrats and the intelligence community to go along with releasing the transcripts. That release is said to be coming soon.

Capitol Hill's secrecy is nothing compared to that of special counsel Robert Mueller, whose lawyers recently declined to tell a federal judge in open court what their investigation is about. It happened in a hearing in the case of former Trump campaign chairman Paul Manafort, who has been charged with financial crimes unrelated to the Trump campaign and the 2016 election.

In court, Mueller prosecutor Michael Dreeben essentially admitted that the May 17, 2017, order appointing Mueller and stating the subject of the investigation was just for show. Mueller's real assignment — the factual statement defining the limits of his investigation — remains a secret. "The regulations nowhere say that a specific factual statement needs to be provided publicly," Dreeben said.

Mueller got his marching orders, Dreeben said, in secret conversations with deputy attorney general Rod Rosenstein. "The specific factual statement … was conveyed to the special counsel upon his appointment in ongoing discussions that defined the parameters of the investigation." It was all done in secret.

Federal District Judge T.S. Ellis' incredulous reply was simple: "Come on, man." Ellis ordered Dreeben to show him the special counsel's complete assignment. That's a good thing — but of course, it will happen in secret. The public still won't know.

And that has been the problem with this investigation, going back to the beginning. In February, I wrote that in the Trump-Russia probe, "Too much material is secret, too much is classified, and too many attacks are launched and defenses mounted with too little public knowledge of the underlying facts."

That's still true, and becoming more so every day.