A white sedan put a man on the loading dock of a glbad and concrete building in a monotonous office district in southwestern Washington. The security guards quickly waved the vehicle, pressed a button that closed the garage door and protected the arrival of the guest from public view.
With his furtive arrival on Thursday morning, White House counselor Donald McGahn became the latest in a series of level witnesses to enter the secret nerve center of special lawyer Robert Mueller III investigating Russian interference in the 2016 elections.
Twenty hours later, Mueller and his team came to the public eye to shake Washington with the dramatic announcement that former national security adviser Michael Flynn would plead guilty to lying to the FBI.
The capture of Flynn, the second former aide to President Donald Trump to cooperate with the investigation, serves as the latest indication that Mueller's operation is carrying out an expansive mission, drilling deeper into Trump's inner circle .
In the past two months, Mueller and his deputies have received private reports from two dozen current and former Trump advisors, each of whom has made the walk to the special attorney's security office.
Once inside, most of the witnesses are sitting in a windowless conference room where teams of two and three people from FBI agents and prosecutors rotate in and out, press them for answers.
Among the topics that have been of great interest to researchers: how foreign government officials and their emissaries contacted Trump officials, as well as the actions and interaction of Flynn and Jared Kushner, son-in-law of the president.
Mueller's group has also asked if Flynn recommended specific foreign meetings for senior advisors, including Kushner The researchers were particularly interested in how certain foreign officials entered the Kushner calendar and the discussions that Flynn and Kushner had about those encounters, according to people familiar with the questions.
Often, listening is the special advice, A presence similar to a sphinx The picture of Mueller's operation, drawn from the descriptions of witnesses, lawyers and others informed about the interviews, provides a rare insight into the high-risk research that could involve the Trump circle. the future of his presidency.
The closed nature of the investigation has left both witnesses and the public scrutinizing I walk every move of the special lawyer in search of meaning, without any certainty about the full scope of his investigation.  Trump and his lawyers have expressed confidence that Mueller will quickly conclude his White House exam, perhaps even by the end of the year. Trump's Democratic opponents hope the investigation will uncover more crimes and ultimately force the president's ouster.
Meanwhile, some witnesses who have been interviewed came away with the impression that the investigation is unfolding and far from over . 19659002] "When they interrogated me, it seemed that they were still trying to get an idea of the basic landscape of the place," said one witness who was interrogated at the end of October for several hours and, like others, spoke about the condition. of anonymity to describe confidential sessions. "I did not have the feeling that they had anything to incriminate the president, they were not even close to doing."
A spokesman for Mueller declined to comment, citing the sensitivity of the ongoing investigation.
White House attorney Ty Cobb said he believes the focus of the Trump White House investigation is ending, noting that all White House personnel interviews will be completed by the end of the week.
"At the end of the interviews, it would be reasonable to expect that it would not take long to bring this to a conclusion," Cobb said. "I congratulate the Office of the Special Adviser for its recognized hard work on behalf of the country, to take on this serious responsibility and carry it out in an accelerated but deliberate and thorough manner."
At least two dozen people who traveled in Trump's orbit in 2016 and 2017 – in campaign, in its transition operation and then in the White House – have been questioned in the last 10 weeks, according to people familiar with the interviews
The most prominent profile is Kushner, w met with Mueller's team in November, as well as former staff chief Reince Priebus and former press secretary Sean Spicer. The former foreign policy adviser J.D. Gordon has also been interviewed.
White House communications director Hope Hicks planned to sit down with Mueller's team a few days before Thanksgiving. Mueller's team has also indicated plans to interview White House badociate advisor James Burnham and political adviser Stephen Miller.
McGahn, who was interviewed by Mueller prosecutors for a full day on Thursday, was due to return on Friday to complete his interview. However, the special attorney postponed the session as a courtesy to allow McGahn to help the White House manage the response to Flynn's statement, a person familiar with the interview said. Cobb refused to say which White House aides remain to be interviewed.
Several people who worked side by side with Flynn were also interviewed by Mueller's operation. That includes retired General Keith Kellogg, chief of staff of the National Security Council, as well as several people who worked with Flynn Intel Group, a now closed private consulting firm.
During the transition, Kushner and Flynn met with the Russian ambbadador to the United States, Sergey Kislyak. At the meeting in early December 2016, Kushner suggested establishing a secure line of communication between Trump officials and the Kremlin at a Russian diplomatic facility, according to US officials who reviewed intelligence reports describing Kislyak's account.
Kushner said Kislyak was looking for the secure line as a way for Russian generals to communicate with the incoming administration about US policy on Syria.
Trump's son-in-law has also been identified by people familiar with his role as the "oldest member" of the transition team that Flynn led in December to approach Kislyak and lobby on a UN resolution on Israeli settlements, according to new court filings.
The volume of questions about Kushner in his interviews surprised some witnesses.
"I remember that they asked me specifically about Jared a number of times," said one witness.
Another witness said that agents and prosecutors repeatedly asked him about Trump's decision: during the weekend of May, he decided to fire the FBI director, James Comey. Prosecutors asked if Kushner had pushed the president to fire Comey, according to two people familiar with the interview.
Kushner's attorney, Abbe Lowell, declined to comment on what the president's son-in-law discussed in his November session with Mueller. "Mr. Kushner cooperated voluntarily with all relevant investigations and will continue to do so," he said.
Two government officials said it would be natural for investigators to ask many questions about Kushner, whom Trump put in charge of communicating with foreign officials, adding that such investigations do not indicate that he is a target.
The special attorney has continued to continuously request the records of Trump campaign badociates, according to two people familiar with the requests. Campaign partners are not expected to finish producing these documents before the end of the year. Mueller's team is also recently examining an Alexandria-based office and advisers who worked there on foreign policy for the campaign.
In recent weeks, Mueller's operation has contacted new witnesses in Trump's circle, telling them that they can be asked to come for an interview. A person who was contacted recently said it is difficult to find a lawyer available to receive advice on how to interact with the special lawyer because so many Trump advisers have already hired lawyers.
"It was a bit painful," said the person. . "It's hard to find a lawyer who is not in conflict."
People who had shown up before Mueller's team describe polite but detailed and intense grills that have sometimes lasted all day and involved more than a dozen researchers. Spicer, for example, was in the office from approximately 10 a.m. until 6 pm. for your fall session. Mueller's team has recommended nearby places for lunch, but many witnesses bring food for fear of being discovered if they go outside.
Mueller has attended some interviews, introducing himself to witnesses as he enters and then sits along the wall. Sometimes he is joined by his friend James Quarles, a former lawyer and friend of Watergate, a former Watergate prosecutor who is the main point of contact for the White House.
Investigators bring large folders full of emails and documents to the interview room. One witness described the barrage of questions that followed each time an agent pbaded them a copy of an email in which they had been copied: "Remember this email? How does the White House work? How does the transition work? Who was taking the "Who was involved in this decision? Who was there that weekend? "
Some witnesses were introduced to so many federal agents and lawyers who later regretted that they had largely forgotten many of their names for when a team left the room and a new team came in.
"They say: 'Hey, we're not trying to be rude, but people are going to come in and go out a lot,'" said one witness, explaining about the equipment. They leave the room. "
A contingent of investigators focuses on whether Trump tried to obstruct justice and avoid investigation into Russian meddling by dismissing Comey in May Prosecutors Brandon Van Grack and Jeannie Rhee have been involved in matters Related to Flynn.
Another team is led by former Department of Justice prosecutor Andrew Weissman and foreign bribery expert Greg Andres. some of the city's most powerful lobby stores about their interactions with former Trump campaign president Paul Manafort and campaign adviser Rick Gates.
Mueller's team accused Manafort and Gates last month of conspiring to hide millions of dollars in hidden foreign accounts and secretly creating an elaborate cover to hide their lobbying work for a former Ukrainian president and his pro-Russian political party. Both have declared themselves innocent.
Lawyers familiar with prosecutors' questions about Manafort said they expect several additional charges for this part of the case.
People familiar with Mueller's team said they convey a sense of calm that is disturbing.
"These guys are safe, awesome, quite friendly, they even joke a little," said one lawyer. When prosecutors play that kind of tone, he said, defense attorneys tend to think, "Uh, my man is in a lot of trouble."
Rosalind S. Helderman, of the Washington Post, contributed to this report.