As Robert Mueller's Russia probe regains momentum after the midterms - where is it headed next?

Analysis: As investigators question more associates connected to Donald Trump's world we are likely entering the beginning of the end to the probe

Set against a White House that has become known for tweets, leaks and tell-all books from former staff, Robert Mueller’s Russia probe has been an oasis of calm and quiet.

The investigation has been virtually leak-proof, even with it representing the shadow which has followed Donald Trump through the entire 18 months of his presidency.

Weeks of public silence about the probe – imposed due to not wanting to undermine the midterm elections which took place earlier in November – look like they are coming to an end and a sense of urgency is returning.

First, a reminder of the scope of special counsel Mueller’s FBI investigation. The brief has been to look into Russian interference in the 2016 US election, and “any links and/or coordination between the Russian government and individuals associated with the campaign of President Donald Trump”.

So far, that has led to 32 indictments or guilty pleas involving around two dozen Russian nationals, three Russian companies and four former Trump campaign officials.

Of those four officials, former Trump foreign policy adviser George Papadopoulos pleaded guilty to making false statements to the FBI, as did Trump’s former national security adviser Michael Flynn.

Not directly related to the investigation into election meddling, former Trump campaign manager Paul Manafort and his associate Rick Gates eventually accepted plea deals having been charged with financial crimes over political lobbying activities in Ukraine. Rick Gates was first, while Manafort was convicted of a number of counts at a trial in Virginia, with a mistrial declared on other counts. Manafort then accepted a plea deal to avoid a second trial in Washington DC.

The Manafort plea is the most interesting of those, as he offered cooperation with the Mueller probe as part of the deal back in September and could possibly be rolled out as a star witness in any future attempts at trials.

As for the president himself, this week he finally submitted written answers to Mueller’s team – who are also looking into the possibility of the president having obstructed the investigation. Mueller and Trump’s legal team have been negotiating for months about a sit-down interview with the president, but Trump has said that is “probably” off the table.

However, Rudy Giuliani – the president’s lead lawyer dealing with the Russia probe, has not ruled out more questions from Mueller. “We’ll consider them and answer them if necessary, relevant and legal,” Giuliani said this week. “If it was something that would be helpful, relevant – not a law school exam.”

The answers to Mueller’s questions from the president relate to the 2016 presidential campaign and the time before Trump was sworn into office, however it is unclear how much the answers go into what happened during the president’s transition into the White House.

Trump’s lawyers have also made clear they would push back against any questions involving the time in office – which includes firing the former head of the investigation then-FBI director James Comey – by citing executive privilege. Trump’s feelings on the investigation have always been clear; there was no collusion and it is a “witch hunt” against him and his administration.

While Mueller could return to Trump once his answers have been assessed, it has not stopped his team from nibbling around the edges of Trump’s world. Conservative commentator Jerome Corsi is the latest to say that he is in plea negotiations with Mueller’s team.

Corsi is an associate of long-time Trump ally and confidante Roger Stone, with questions likely to be surrounding Wikileaks and the release of thousands of Democrat emails in the last weeks of the 2016 election. It could bring Mueller’s team closer to determining whether Trump or his advisers were linked to the release of the emails.

During the 2016 campaign, Stone publicly bragged about having “backchannel communications” with WikiLeaks founder Julian Assange, and on several occasions appeared to predict the WikiLeaks releases.

The questions Corsi has likely faced in his hours of interviews with investigators relate to any possibility he acted as an intermediary for Stone.

In the two years since the election, Stone has walked back his claims and Wikileaks have also denied coordination. Stone denies that he ever told Trump about WikiLeaks’ dumps before they became public. He also denies colluding with Russia.

However, it seems clear that Mueller’s team seem certain that talking to Stone’s associates, and maybe eventually Stone himself, could open up new avenues of inquiry.

Beyond the minutiae of the investigation, there have been growing fears in Congress about the threat of interference with Mueller’s probe as he enters the beginning of the end of the investigation. Those worries have been exasperated by Trump using the end of the midterms as an excuse to force out the attorney general Jeff Sessions and replace him with the acting attorney general Matthew Whitaker.

Sessions had recused himself from the Russia probe last year, with deputy attorney general Rod Rosenstein overseeing the investigation. However, Whitaker – who has previously expressed doubts over the scope of Mueller’s activities and suggested cutting funding is a way to limit them – is now in charge.

A number of attempts have been made to challenge Whitaker’s appointment in the courts, while legislation protecting Mueller has been suggested in the Senate, but knocked back by Republican Party leadership.

Amid it all, Mueller and his team have silently been going about the business of gathering potential evidence. Mueller is the only one that knows how far away he is from finishing, and the probe could stretch into next year given how close we are to Christmas. But do not bet against the type of surprise indictments, or even the full report, that Mueller and his team have so far been able to keep veiled from the prying eyes in Washington DC.