A TV interview given by President Trump in the days after he fired James Comey proved a key moment in building suspicions against him. Photograph by Christopher Anderson / Magnum

On Friday evening, the Times reported that, days after President Trump fired the F.B.I. director James Comey, on May 9, 2017, the Bureau opened a counterintelligence investigation into whether the President, knowingly or unknowingly, “had been working on behalf of Russia against American interests.” When, on May 17th, Deputy Attorney General Rod Rosenstein appointed Robert Mueller to conduct the investigation into Russian interference in the 2016 Presidential election, Mueller reportedly took over the counterintelligence inquiry into Trump, along with the previously known criminal investigation.

To discuss the Times piece, I spoke by phone with Adam Goldman, who reported the story along with Michael S. Schmidt and Nicholas Fandos. During the course of our conversation, which has been edited and condensed for clarity, we discussed why the F.B.I. felt it had to take such an extreme step, the atmosphere in the Bureau after the Comey firing, and whether the Mueller investigation is really nearing its end.

How long have you been working on this particular story?

I have been working on this story for quite some time. [Laughs.] I don’t want to say too long, but a while.

What’s your biggest takeaway from it?

My concern with this story is that it felt, to some extent, like it was a “duh” story. What does the public think Mueller is doing? The public’s understanding of it is “Oh, well, Mueller is looking at whether Trump colluded with the Russians.” But nobody has ever detailed or explained the basis of that thinking, right? Do you understand what I am saying?

You are saying that we all thought this is what was going on, but all we really knew was that the F.B.I. had an obstruction investigation. We didn’t know that there was a counterintelligence investigation—

I think a lot of people have assumed that, and I have seen other reporters just write it: “Mueller is investigating whether Trump colluded with the Russians.” I think that is the general theme here, but once somebody told me about it in some detail, I thought it was important to lay out just what had happened, and to explain to the public that, yes, you are right—everyone knew there was an obstruction piece to this, but there was another piece to it that happened at the same time. It is two elements of one investigation: a criminal one and a counterintelligence one.

Do you—

My fear was that the nuance—this is a heavily nuanced story—would get lost on the public. And I had to understand the nuance and I had to understand the story, and that contributed to the time it took to write this and publish it.

What aspect of it were you worried would be missed if it wasn’t nuanced?

What this means, right? That the F.B.I. had specifically started looking at Trump and whether he wittingly or unwittingly had been working with a hostile foreign power. I had to look at the mechanisms that went into place to trigger this aspect of the investigation. This comes after the Lester Holt interview. [On May 11th, 2017, two days after Trump fired Comey, the President gave an interview to NBC in which he said that, when he fired Comey, he was thinking, “You know, this Russia thing with Trump and Russia is a made-up story.”] And you talk to people who are familiar with this: once he got on Lester Holt and he said this, the F.B.I. is, like, “He is telling us why he did this? The President of the United States got up on television and said, ‘I did this because of Russia.’ ” They are, like, “What the fuck?,” right? Once again it is the President and these self-inflicted wounds. The President said that, and forgive the F.B.I. for taking him at his word. And that led to the opening of the investigation on Trump himself, before the appointment of the special counsel.

What would that look like if the President was an unwitting agent of a foreign power?

Did somehow Russia exert some pressure on Trump, maybe not necessarily because it has leverage or blackmail, but somehow they devised a way to get him to operate on their behalf, to do something on their behalf? It is hard to say what that would look like. People were very careful to tell me that: “It is wittingly or unwittingly. We are not here to say that Trump is an agent of a foreign power.”

Does this change your sense of the Mueller investigation?

No, not necessarily. Mueller inherited this when he became special counsel, and this is something he would have had to run to the ground. Now we know it officially exists, and it was a predicated F.B.I. investigation, and they would have to articulate why they would have to open this investigation. Mueller inherited this, and he will have to end it. And it seems to me he will have to articulate, if he hasn’t already, why there wasn’t evidence to support this idea—or maybe there was. I think Mueller is going to have to address this. Which, by the way, is the question the American public expects him to answer. You don’t need me to tell you that the American public expects an answer to “Is Trump working with Russia?” It’s the sixty-four-thousand-dollar question.

Were you concerned, or were the people you talked to concerned, about a counterintelligence investigation being opened on the President of the United States, and whether that was a dangerous thing for a democracy?

I asked that question, and the answer was that this was a lawfully predicated investigation. And my understanding was that the people involved understood the gravity of it and knew they would have to answer for it someday, when Congress conducted oversight. Eventually, this will become public. The people who do this kind of work are not fools and know it will become public, just like the Carter Page FISA application became public.

They will have to answer for this if, in fact, the predication of the investigation was weak. My understanding is that people felt the evidence to open this was quite strong, and the comments to Lester Holt pushed it over the edge. It’s my understanding that, if they hadn’t opened this, it would have been an abdication of their duty. If you are a law-enforcement official and you have evidence that perhaps suggests that the President himself may be acting as a foreign agent, either wittingly or unwittingly, isn’t it your duty to run this to the ground?

The problem with this investigation, as anyone in the F.B.I. will tell you, is that normally this is done secretly. The public isn’t supposed to know. Normally, the Russia investigation, Crossfire Hurricane [its code name], would have been done quietly. If word hadn’t gotten out, and they hadn’t found anything on these people, maybe the American public would never have known the investigation had gone on. That is what is supposed to happen.

Do you get the sense that, in the days after the Comey firing, people in the F.B.I. were acting rationally? Your paper’s story about Rosenstein considering taping the President also suggested that agents were understandably stressed, scared, and anxious and hinted—