James B. Comey. (Chip Somodevilla/Getty Images)

Few questions in the aftermath of the firing of FBI Director James B. Comey are as critical to answer as how the move by President Trump affects the investigation into possible links between Trump’s presidential campaign and Russian figures.

While investigations are also ongoing in the House and Senate, much of that effort is conducted in public by politicians eager for media attention and led by members of Trump’s own party.

The FBI investigation, by contrast, was conducted in secret by career investigators untethered to partisan politics — except that the head of the organization serves at the pleasure of the president. How that investigation will move forward now that Comey has been removed remains to be seen.

So what do we know about how that investigation has moved forward so far? Not much. Both Comey and former acting attorney general Sally Yates — also fired by Trump — have spoken about the investigation in congressional hearings but, without the protection of being able to speak freely about classified information, weren’t able to reveal much. We went back over four hearings in which Comey and Yates participated and pulled out what each had said which might provide some insight.

Comey was asked about the existence of any investigations between either 2016 candidate’s campaign and Russian actors during a Senate Intelligence Committee on Jan. 10, 10 days before Trump was sworn in as president.

“Especially in a public forum,” Comey told Sen. Angus King (I-Maine) in January, “we never confirm or deny a pending investigation.” King replied that there was some irony in Comey’s saying that, alluding to Comey’s comments about the investigation into Hillary Clinton’s email server the prior year. Comey replied that closed investigations — which Clinton’s was — could be discussed.

In early March, now-President Trump tweeted an accusation that the Obama administration had wiretapped phones at Trump Tower in order to obtain information about his campaign — a claim that was based on loosely sourced reports in conservative media and for which no evidence has subsequently emerged. In the wake of that accusation, we reported that Comey had asked the Justice Department to rebut the charge, which didn’t happen.

Two weeks later, before the House Intelligence Committee, Comey was given the authorization to speak publicly about an investigation that was in progress. His opening statement addressed the question immediately.

I have been authorized by the Department of Justice to confirm that the FBI, as part of our counterintelligence mission, is investigating the Russian government’s efforts to interfere in the 2016 presidential election and that includes investigating the nature of any links between individuals associated with the Trump campaign and the Russian government and whether there was any coordination between the campaign and Russia’s efforts. As with any counterintelligence investigation, this will also include an assessment of whether any crimes were committed.

Because it is an open ongoing investigation and is classified, I cannot say more about what we are doing and whose conduct we are examining. At the request of congressional leaders, we have taken the extraordinary step in coordination with the Department of Justice of briefing this Congress’ leaders, including the leaders of this committee, in a classified setting in detail about the investigation but I can’t go into those details here. I know that is extremely frustrating to some folks. I hope you and the American people can understand.

He later indicated that the investigation “began in late July.” As of early December 2016, Comey said, the FBI had determined that Russia’s goal in its campaign interference was “to hurt our democracy, hurt her, help him” — that is, hurt Clinton and help Trump.

Asked by ranking member Adam B. Schiff (D-Calif.) if he could corroborate Trump’s tweets, Comey said he could not.

“With respect to the president’s tweets about alleged wiretapping directed at him by the prior administration, I have no information that supports those tweets and we have looked carefully inside the FBI,” Comey said. “The Department of Justice has asked me to share with you that the answer is the same for the Department of Justice and all its components. The department has no information that supports those tweets.”

That tells us something about the investigation: That while the FBI was actively investigating links between the campaign and Russia, there was likely no surveillance of the campaign’s main headquarters in Trump Tower.

What prompted the investigation? Comey spoke to this broadly.

“Don’t you need some action or some information besides just attending a meeting, having been paid to attend a conference, that a picture was taken, or that you traveled to a country before your open to investigation for counterintelligence by the FBI?” Rep. Michael R. Turner (R-Ohio) asked, hoping to narrow down why the FBI had stepped in.

Comey described the standard for an investigation as requiring “a credible allegation of wrongdoing or reasonable basis to believe that an American may be acting as an agent of a foreign power” — indicating that such a question arose around the Trump campaign.

Asked if he agreed with a statement from former Director of National Intelligence James R. Clapper Jr. that there was no evidence of collusion between Trump’s campaign and Russia included in the report compiled by the intelligence agencies, Comey said Clapper was “right about characterizing the report which you all have read” — though this leaves open the question of whether or not such evidence existed without being included.

He also pointed out that the FBI’s counterintelligence investigation was kept within the Bureau and not shared with other agencies or Congress until well after it started.

“I think our decision was it was a matter of such sensitivity that we wouldn’t include it in the quarterly briefings,” Comey said. That echoes what Yates said when she, too, was asked about Clapper’s comment during a Senate Judiciary subcommittee on Monday.

While Comey consistently demurred when pressed to answer questions about who might be targeted in the investigation, Yates confirmed that former national security adviser Michael Flynn was included — as was obvious after Flynn was dismissed for misrepresenting conversations he’d had with the ambassador to Russia that were recorded by federal agents.

Sen. Richard Blumenthal (D-Conn.) asked Yates if she’d told White House counsel Don McGahn that Flynn had lied to the FBI. She said that she “specifically declined to answer that.” When Blumenthal asked if this was because it was part of an investigation, she said that was correct.

In his letter terminating Comey, Trump self-consciously mentioned having been told on three separate occasions by Comey that he himself was not being investigated. What this refers to isn’t clear; on Wednesday, deputy press secretary Sarah Huckabee Sanders said that she was “not going to comment any further than what was spelled out in the letter.”

When he appeared before the Senate Judiciary Committee on May 3, Comey was asked if Trump was targeted, and he demurred.

“You have not, to my knowledge, ruled out anyone in the Trump campaign as potentially a target of that criminal investigation, correct?” Blumenthal asked him.

“Well, I haven’t said anything publicly about who we’ve opened investigations on, I briefed the chair and ranking on who those people are,” Comey replied. “And so I can’t — I can’t go beyond that in this setting.”

“Have you — have you ruled out the president of the United States?” Blumenthal later asked.

“I don’t — I don’t want people to over interpret this answer, I’m not going to comment on anyone in particular, because that puts me down a slope of — because if I say no to that then I have to answer succeeding questions,” Comey answered.

Later still, Blumenthal asked if the White House was cooperating with the investigation. “That’s not something I’m going to comment on,” Comey said.

Sen. Al Franken (D-Minn.) asked why Comey thought that Trump was preferred by the Russians.

Comey’s reply:

One is he wasn’t Hillary Clinton, who Putin hated and wanted to harm in any possible way, and so he was her opponent, so necessarily they supported him.

And then also this second notion that the intelligence community assessed that Putin believed he would be more able to make deals, reach agreements with someone with a business background than with someone who’d grown up in more of a government environment.

It’s not clear if this derived from the investigation or not.

Comey did confirm that a party calling himself “Guccifer 2.0″ who was involved in leaking some information that the government believes was stolen by Russians was “an instrument of the Russian intelligence” — important to the story because Trump ally Roger Stone admitted to communicating (innocuously, in his telling) with Guccifer over Twitter.

That’s about the extent of what was said. Two other comments from the May 3 hearing, though, are resonant in light of Comey’s firing.

What would he do if he encountered a roadblock in his investigation, Blumenthal asked, given that he was still reporting to the administration he was investigating?

“If there was a challenge with any investigation that I couldn’t resolve at the working level, I would elevate it to the Deputy Attorney General or whoever was in charge of it,” Comey said.

Blumenthal noted that this was a conflict of interest, given that the deputy attorney general reported to Trump.

“It’s — it’s a consideration but also the nature of the person in the role is also very important consideration,” Comey said. “I think we’re lucky to have somebody who thinks about the Justice System, very similar to the way I do and Pat Fitzgerald does and the way you did.”

Fitzgerald was a special counsel appointed by Comey to look into a leak of information about CIA agent Valerie Plame during the Bush administration. The deputy attorney general to whom Comey reported was Ron Rosenstein, who wrote the letter Trump used as his rationale to fire Comey.

Comey was also asked by Blumenthal if he regretted any of his actions surrounding the Clinton email investigation.

“Yes, the honest answer is no,” Comey replied. “I’ve asked myself that a million times because, lordy, has this been painful.”

He continued. “The only thing I regret is that maybe answering the phone when they called to recruit me to be FBI director when I was living happily in Connecticut.”

Blumenthal, who represents the state, assured Comey that he’d be welcomed back.