On a cloudy day in early November, the last of conservative writer Jerome Corsi's six marathon interviews with the office of special counsel Robert Mueller was about to begin. Sitting in a building in Washington, three prosecutors assigned to his case opened with a lecture.

For more than two months, they had been chasing tantalising leads offered by Mr Corsi, an associate of Donald Trump confidant Roger Stone, who had told them that the longtime Republican Party operative sought a back channel to WikiLeaks during the 2016 campaign.

They had dispatched FBI agents around the country to interview potential witnesses, expending valuable government money and precious time - only to find themselves unable to untangle Mr Corsi's assertions that Mr Stone knew in advance that WikiLeaks would be releasing emails stolen from the account of John Podesta, Hillary Clinton's campaign chairman.

"No lies, hunches, wishes," prosecutor Aaron Zelinsky lectured Mr Corsi that day as they sat in a windowless conference room, according to notes taken by Mr Corsi's lawyer, David Gray. "Hopes do not equal facts. Don't tell us what you think we want to hear."

The Yale University-educated former Supreme Court clerk pleaded with Mr Corsi: It was "vitally important" that Mr Corsi provide the "truth only," Mr Zelinsky said.

Criminals who worked for Trump Show all 5 1 /5 Criminals who worked for Trump Criminals who worked for Trump Michael Cohen Former lawyer for Donald Trump was sentenced to three years in prison on counts involving evading income tax, false disclosure of the hush money paid to Stormy Daniels and another hush money charge Getty Criminals who worked for Trump Paul Manafort Former campaign manager for Trump Manafort was found guilty in February 2018 of five counts of tax fraud, two counts of bank fraud and one count of failure to disclose a foreign bank account. The crimes occurred prior to his appointment in Trump's campaign Getty Criminals who worked for Trump George Papadopoulos Former Trump campaign adviser Papadopoulos pleaded guilty to lying to the FBI in October 2017. He had lied about making contact with a professor who claimed that the Russians had dirt on Hillary Clinton. He was sentenced to 14 days in jail Getty Criminals who worked for Trump Michael Flynn Former White House National Security adviser Michael Flynn pleaded guilty to lying to the FBI in December 2017. He had lied about conversations that he had with the Russian ambassador to the US during Trump's Presidential campaign. He was not given prison time due to his "significant assistance" to the Mueller investigation Getty Criminals who worked for Trump Rick Gates Deputy chairman of Trump's presidential campaign Gates pleaded guilty to lying to the FBI in February 2018 AFP/Getty

The trio of top prosecutors had spent weeks coaxing, cajoling and admonishing the conspiracy theorist as they pressed him to stick to facts and not reconstruct stories. At times, they had debated the nature of memory itself.

Once again that day, however, Mr Corsi struggled to answer clearly questions about Stone and WikiLeaks - closing the door on an exhausting final chapter of Mr Mueller's nearly two-year hunt to determine whether anyone in Donald Trump's world had coordinated with Russia.

The investigation took the special counsel's team down several meandering paths, propelled by discoveries of unusual interactions between Trump associates and Russians. Trump campaign Chairman Paul Manafort had shared internal information with an employee assessed by the FBI to have Russian intelligence ties. Foreign policy adviser George Papadopoulos was tipped off that the Russians had thousands of Ms Clinton's emails. Donald Trump Jr met with a Russian lawyer who he hoped would offer damaging information about Ms Clinton.

In the end, Mr Mueller's final report, a redacted version of which was released by Attorney General William Barr last week, laid out new details about the Russian effort to influence the 2016 campaign through social media and the hacking of Democratic emails, and it offered a rich portrait of Trump's efforts as president to undermine the investigation and mislead the public.

The 448-page report also revealed the outcome of the long endeavour to determine the relationship between Trump associates and Russia: some unanswered mysteries, a lot of dead ends and, ultimately, a conclusion that the contacts they found did not establish a criminal conspiracy.

Trump and Farage - a working friendship Show all 7 1 /7 Trump and Farage - a working friendship Trump and Farage - a working friendship Donald Trump and Nigel Farage pose in the golden elevator at Trump Tower on 12 November 2016, four days after Trump was elected president. Farage was the first British politician to meet with Trump after the election LeaveEUOffical/Twitter Trump and Farage - a working friendship Not long after their meeting at Trump Tower, then-president elect Trump tweeted in favour of Nigel Farage being appointed ambassador to the US Trump and Farage - a working friendship Farage appears at a Trump campaign rally in Jackson, Mississipi on 24 August 2016. Farage drew parallels between the recent vote for Brexit in the UK and a vote for Trump in the US, saying "they could take back control of their country, take back control of their borders and get back their pride and self-respect" Getty Images Trump and Farage - a working friendship Trump introduced Farage as "Mr. Brexit" Getty Images Trump and Farage - a working friendship President Trump with Nigel Farage when they met met face-to-face to discuss why the President should back a no-deal Brexit on 3 March 2019 PA Trump and Farage - a working friendship From left to right: Gerry Gunster (US pollster and campaign adviser to Leave.EU), Arron Banks (Leave.EU founder who is being investigated over the funding of the Brexit campaign), Donald Trump (then president-elect), Nigel Farage (then leader of UKIP), Andy Wigmore (communication director of Leave.EU) and Raheem Kassam (then-advisor to Farage and later UK editor of Breitbart news) Trump and Farage - a working friendship Farage and his adviser Raheem Kassam arrive to meet with Trump on November 12 2016 Getty Images

Mr Stone has not been charged with serving as a conduit to WikiLeaks, which disseminated material stolen by Russians.

Instead, he was indicted in January for lying to Congress about his efforts to reach out to WikiLeaks. He has pleaded not guilty and has vehemently denied having any knowledge of what WikiLeaks held and the group's exact plans. Mr Stone has also denounced Mr Corsi's account as lies.

Mr Corsi announced in November that he had rejected a deal to plead guilty to false statements and accused the special counsel's office of trying to bully him into lying. He has not been charged with any crime.

A reconstruction of the laborious effort by Mr Mueller's team to determine whether the Trump campaign conspired with Russia shows why it was often a maddeningly difficult task.

Their witnesses were not ideal. A few key players, prosecutors would contend, lied in interviews. Many were loyal to the president and echoed his rhetoric that Mr Mueller's team was acting in bad faith. Some used encrypted applications with disappearing messages that could not be reviewed. Others were overseas, unreachable to American investigators.

Kellyane Conway refuses to say whether Trump tried to fire Robert Mueller

In some cases, their statements were only loosely tethered to the facts.

This account is based on interviews with people who interacted with Mr Mueller's team, court documents and new details laid out in the special counsel's report. A spokesman for the special counsel's office declined to comment for this story.

Open to Russian help

It was the first item in the order that Deputy Attorney General Rod Rosenstein issued in May 2017 when he appointed Mr Mueller as special counsel.

As part of his charge, Mr Mueller would take over a pre-existing FBI investigation into "any links and/or coordination between the Russian government and individuals associated with the campaign of President Donald Trump."

The inquiry had begun in late July 2016 after the Australian government contacted the FBI about Papadopoulos. Over drinks at a bar in London, the young Trump aide had confided to an Australian diplomat that the Russian government had thousands of Clinton emails that could damage her candidacy.

By the time Mr Mueller was appointed, the FBI had interviewed Papadopoulos and, according to him, tried unsuccessfully to get him to travel to London and surreptitiously record a conversation with Joseph Mifsud, a Maltese professor who told him about the Clinton emails. In a 2017 interview with a British newspaper, Mifsud denied knowledge of the emails.

The FBI had also obtained a secret court order allowing it to monitor the communications of former Trump adviser Carter Page, who had travelled to Moscow during the heat of the campaign and interacted there with a Russian government official.

Donald Trump shares a no collusion megamix on Twitter

The work came against the backdrop of the publication of a research dossier prepared by a former British intelligence agent and funded by Ms Clinton's campaign, which said Mr Trump had engaged in a knowing conspiracy with Russia, which Mr Trump dismissed as false.

The special counsel moved quickly on several fronts.

Weeks after Mr Mueller was appointed, the FBI sent a search warrant to Google, scooping up Trump attorney Michael Cohen's Gmail messages dating back to January 2016, court records show. His emails began to help investigators uncover the extent of his efforts to develop a Mr Trump Tower project in Moscow - an attempt that persisted through much of the campaign, even as Trump publicly denied that he had business ties in Russia, court filings show.

By July, Mr Mueller's team was delving into Trump Jr's meeting the previous summer with Russian lawyer Natalia Veselnitskaya, which had also been attended by Trump's son-in-law Jared Kushner and Manafort.

They started with a potentially neutral witness: the interpreter, interviewing him just four days after The New York Times broke the news of the meeting, according to the report.

Russian-born Anatoli Samochornov described to investigators what unfolded in the 20-minute meeting: Ms Veselnitskaya raised the topic of Democratic donors who she said had broken Russian law. One of her associates then brought up a US sanctions law against Russia and a ban on American adoptions of Russian children that the Kremlin had imposed in retaliation. Mr Trump Jr said there was little his father could do to address the issue, but he said it could be revisited if Mr Trump were elected.

In November 2017, prosecutors interviewed Ike Kaveladze, an employee of Aras Agalarov, the Russian billionaire who had hosted Mr Trump's Miss Universe pageant in 2013 in Moscow and requested the meeting through the candidate's son.

"They asked very targeted questions," said Mr Kaveladze, who had attended the meeting as the Agalarov representative. "I realised they had significant knowledge of the topic."

Mr Mueller's team interviewed everyone who attended the meeting except Ms Veselnitskaya, who is in Russia, and Trump Jr, who declined to participate voluntarily, they wrote. (It is unclear whether prosecutors attempted to subpoena the president's son.)

The picture that was emerging was one of a campaign that was eager for Russia's help at the same time the Kremlin had been working to elect Mr Trump.

As 2017 stretched on, former national security adviser Michael Flynn pleaded guilty to lying to the FBI about his communications with the Russian ambassador during the transition. Papadopoulos pleaded guilty to lying about his contacts with Mifsud and two Russians.

By July 2018, Mr Mueller had charged 25 Russians with participating in two plots to influence the White House race.

But the special counsel still had not resolved whether Russia coordinated with Trump associates.

A possible break in the case

In September 2018, Mr Mueller's team got a break. Mr Manafort, who had been a central figure in the investigation from the start, agreed to plead guilty to financial crimes and not registering as a foreign lobbyist for work he had conducted in Ukraine before leading the Trump campaign.

At last, prosecutors had access to a key member of Mr Trump's inner campaign circle who also had deep connections in Russia, including a business relationship with Oleg Deripaska, a billionaire with close ties to Russian President Vladimir Putin.

Manafort's deputy, Rick Gates, told prosecutors that, as soon as Manafort joined the campaign, he had asked Gates to prepare memos describing his elevated new role for Mr Deripaska and three leading Ukrainian politicians. Emails show Manafort tried to get a message to Mr Deripaska to offer him private briefings about Mr Trump's effort. Manafort told investigators he never gave Mr Deripaska such briefings.

Manafort's liaison to the Russian aluminium magnate was his own longtime Russian employee, Konstantin Kilimnik, who the FBI had assessed had ties to Russian intelligence, according to the special counsel.

The report said Manafort also provided campaign polling data to Mr Kilimnik, described to him a strategy to win the election for Mr Trump by contesting traditionally Democratic leaning Midwestern states and discussed with him a pro-Russian peace plan for Ukraine, a top foreign policy goal of the Kremlin. Manafort would later say he understood Mr Trump, if elected, would need to approve the plan for it to advance.

Manafort's cooperation meant prosecutors had a firsthand witness who could explain whether there was ever a suggestion of a trade-off: Russian assistance in the campaign in exchange for a Trump administration that supported pro-Russian policies.

On 11 September 2018, Manafort sat for the first of 11 interviews with investigators. He also appeared twice before the grand jury.

But, prosecutors said, he did not tell them everything he knew. A federal judge agreed, ruling in February that Manafort had lied intentionally to prosecutors, particularly about his interactions with Mr Kilimnik.

"It's part of a pattern of requiring the Office of Special Counsel to pull teeth - withholding facts if he can get away with it," US District Court Judge Amy Berman Jackson said during a February hearing.

In an email to The Washington Post last week, Mr Kilimnik denied he had Russian intelligence ties and said he had not shared the polling information with anyone else. He said he had "absolutely . . . zero" to do with Russian interference.

Attention turns to Corsi

Meanwhile, several prosecutors on Mr Mueller's team were pursuing another intriguing subject: Stone, who had a decades-long friendship with Mr Trump and who had worked briefly for the celebrity mogul's campaign in 2015 and then continued to informally advise him.

During the campaign, Mr Stone egged on WikiLeaks as the London-based group released materials prosecutors say were provided by Russian operatives to help elect Mr Trump. Starting in early August 2016, Mr Stone began bragging publicly that he had a way to communicate with WikiLeaks founder Julian Assange.

On 21 August 2016 - six weeks before WikiLeaks published emails stolen from Mr Podesta - Stone tweeted, "Trust me, it will soon the Mr Podesta's time in the barrel."

The seemingly prescient and imperfectly phrased tweet did not mention WikiLeaks. But it led to suspicions by Mr Podesta and others that Stone had been aware of WikiLeaks' plans in advance.

For months, Mr Mueller's team sought to understand whether Mr Stone shared information about WikiLeaks' activities with the campaign, uncovering numerous examples of Mr Trump's deep interest in the Clinton emails.

At one point, during a drive to LaGuardia Airport, Mr Trump told senior campaign official Mr Gates that "more releases of damaging information would be coming," he later told prosecutors.

Some in Mr Trump's orbit appeared to view Stone as having a hand in WikiLeaks' activities. One person affiliated with a Trump campaign aide sent Mr Stone a text message just after WikiLeaks published Mr Podesta's emails on 7 October 2016. "Well done," read the message, according to Stone's eventual indictment, which did not identify the sender.

After the election, Mr Stone vociferously and repeatedly denied that he had been in contact with Mr Assange or had any heads-up about WikiLeaks' plans. He said that he never discussed WikiLeaks with Mr Trump and that his claims during the campaign were just boasts and exaggerations.

Likewise, in written answers prepared by his attorneys, Mr Trump told prosecutors he did "not recall discussing WikiLeaks" with Stone or being aware of Stone discussing the subject with others on his campaign, according to the report.

In September 2017, Mr Stone testified to the House Intelligence Committee that his public hints about WikiLeaks were based on vague tips he'd been given by a New York radio host and comedian named Randy Credico, whom he described as an "intermediary" and "mutual friend" of Assange.

Mr Credico has denied serving as a back channel for Stone. He said he didn't become acquainted with Mr Assange until the WikiLeaks founder appeared on his radio show on 25 August 2016. Stone began talking publicly about having a line to WikiLeaks weeks earlier.

Did Mr Stone have another source? Prosecutors wanted to find out.

They brought Mr Credico - along with his small white therapy dog Bianca - to Washington to testify before the grand jury. The panel interviewed Kristin Davis, a close Stone friend once known as the "Manhattan Madam" because she used to run a prostitution business catering to wealthy New Yorkers. They issued a subpoena to Mr Stone's business assistant and held him in contempt of court when he refused to testify.

The grand jury then turned its attention to Mr Corsi, a conservative author who had emailed with Mr Stone about WikiLeaks during the campaign.

Mr Corsi, 72, had at one point worked in financial services, but more recently had become a popular writer on the fringe right. He wrote a book in 2004 accusing then-presidential candidate John Kerry of lying about his Vietnam service and then became a leading proponent of the false theory that President Barack Obama was not born in the United States, a topic over which he bonded with Mr Trump.

On 28 August 2018, two FBI agents banged on the door of Mr Corsi's New Jersey home, a grand jury subpoena in hand - starting a byzantine turn in the investigation.

After convening with Mr Gray, a New Jersey attorney who had done legal work for his wife's cleaning business, Mr Corsi decided he would cooperate with prosecutors. He agreed to turn over his computers and passwords to his social media accounts and to sit for voluntary interviews.

But Mr Corsi's first meeting in September with prosecutors Mr Zelinksy, Andrew Goldstein and Jeannie Rhee went quickly awry, Mr Gray said in an interview with The Washington Post.

Mr Corsi issued a blanket denial about having anything to do with WikiLeaks during the campaign. He claimed that he had told Stone during the campaign that trying to contact Assange was a bad idea that could subject them both to investigation, according to a draft court filing.

That wasn't accurate.

By then, prosecutors had obtained emails showing that Mr Corsi was in constant conversation with his friends and contacts, including Stone, throughout the final months of the campaign, speculating about Assange's next moves, according to Mr Gray.

On July 25, 2016 - a few days after WikiLeaks upset the Democratic National Convention by publishing internal Democratic Party emails - Stone emailed Mr Corsi and asked him to get to Assange and find out what else the WikiLeaks founder held, according to a draft plea agreement Mr Corsi released.

Mr Corsi forwarded Mr Stone's note to Ted Malloch, an American author living in London who hoped to land a job with Mr Trump and was eager to curry favour with his campaign, according to the draft filing.

According to the report, Malloch told prosecutors he never tried to reach Assange, who was living at the Ecuadoran embassy. He declined to comment.

Eight days later, Mr Corsi sent Stone an email, hinting that he had managed to pick up new intelligence on Assange: "Word is friend in embassy plans 2 more dumps." He predicted one of WikiLeaks' publications would come in October and referenced Mr Podesta, according to the draft filing: "Time to let more than Mr Podesta to be exposed as in bed w enemy if they are not ready to drop HRC."

Mr Corsi has said he was never in direct or indirect contact with Assange. He said he was exaggerating his knowledge to Mr Stone.

"I'm convinced my memory is correct that I didn't have a source that connected me to Mr Assange," he told The Post in November. "I really don't think so."

But prosecutors used his initial assertion that he declined Mr Stone's request to seek information from WikiLeaks as a cudgel, saying he could be charged with a crime for lying, Mr Corsi described in a book he wrote about the experience called "Silent No More" that was published in December.

They pressed him to explain: Did he ever reach Assange? Did he tell Mr Stone in advance that WikiLeaks had Mr Podesta's emails? Did he and Mr Stone help WikiLeaks time the releases for maximum impact?

Mr Gray said that he believed Mr Corsi was trying to be honest, but he acknowledged that his client's answers were not always clear or consistent.

He said he decided to share details from Mr Corsi's sessions with prosecutors - including reading to The Post from contemporaneous notes - to try to help the public better understand how the clash between the special counsel's office and witnesses like Mr Corsi frustrated and extended the investigation.

Mr Corsi, he noted, had sold thousands of books and built a fan base by cherry-picking facts to craft a desired narrative. For Mr Corsi, this wasn't lying, but salesmanship, picking "truthful facts woven in a way that you don't have to worry about the things that are inconsistent," Mr Gray said.

The deeply fact-based prosecutors struggled to make sense of the conspiracy theorist and his evolving testimony.

"It's their biggest nightmare," Mr Gray said. "The supposed best of the best were just frankly dumbfounded by the whole situation."

'His answer had morphed'

Over sessions in September and October, Mr Corsi offered information that appeared enticing but sketchy.

Mr Corsi said he had figured out on his own in early August 2016 that WikiLeaks had Mr Podesta's emails. According to the report, Mr Corsi told Malloch in August or September that WikiLeaks would be releasing Mr Podesta's emails and then the Trump campaign would be "in the driver's seat."

Mr Corsi also told prosecutors that he alerted Stone that Mr Podesta's emails were coming and believed Mr Stone's "barrel" tweet was based on his information, Mr Corsi has said.

He said he and Mr Stone had then crafted a "cover story" after the tweet to avoid tipping people off to their information - a research memo Mr Corsi submitted to Stone with information about John and his brother Tony Podesta's business ties to Russia.

Stone told Congress that conversations he'd had with Mr Corsi about the memo was the basis for his tweet, even though the memo was dated 31 August 2016 - 10 days after he posted his message on Twitter about Mr Podesta.

Mr Gray said prosecutors appeared skeptical of Mr Corsi's claim that he had merely divined on his own that WikiLeaks would be releasing Mr Podesta's emails after determining that they were not included in the cache of the Democratic Party emails the group released in July. (Mr Podesta, after all, did not work for the DNC, and his emails were not kept on the party committee's servers.)

Over and over, they asked Mr Corsi who had told him WikiLeaks held Mr Podesta's emails and whether he'd communicated with Mr Assange. At one meeting, Mr Gray said Mr Corsi seemed to concede that another person might have "planted a seed" in his mind about what WikiLeaks held. Then he said "maybe he heard it from somewhere," Mr Gray said.

"His answer had morphed a bit. It was concerning to me, and it was concerning to the prosecutors," he said.

In his book, Mr Corsi insisted the prosecutors confused and rattled him with their repetitive questioning. At one point, he said he told the trio: "It frustrates me that I can't remember. . . . Sometimes I can't tell if I remembered or invented.'"

Mr Corsi told The Post in an interview last week: "I did not go in to lie or deceive them."

"I told them from the beginning that I couldn't remember my 2016 conversations with the kind of precision they were going to demand," he said, adding: "I'm not a human tape recorder."

The group spent many hours in a windowless conference room, with the three prosecutors and six FBI agents arrayed on one side of the table and Mr Gray and Mr Corsi on the other.

At one point, Mr Gray recalled that his eyes wandered to a whiteboard that covered one wall of the room. It appeared to have been only recently erased from an earlier meeting, and he could just barely make out what had been written there previously:

"Ukraine," it said faintly, underlined three times, an apparent reference to Mr Manafort's interviews, which were underway during that period. Beneath that were dollar figures tallying into the tens of millions.

Donald Trump talks about the size of Texas

A dead end in Texas

Among Mr Corsi's assertions to prosecutors, according to Mr Corsi's book: that Stone had given him advance notice on 7 October 2016, that The Post would be publishing a video in which Mr Trump could be heard coarsely bragging about groping women.

Mr Corsi said Stone had urged him to reach Assange and get him to release whatever he'd been holding back to counter the damaging video.

About a half-hour after The Post published a story about the video, WikiLeaks did, in fact, post the first tranche of thousands of Mr Podesta emails.

If there was evidence that Mr Stone played a role in the timing of the Mr Podesta release, it would support the case that there was a conspiracy.

Mr Stone has denied knowing anything about the tape in advance or playing a role in the timing of the Mr Podesta release.

Mr Corsi also told investigators that he believed he had played a role in getting WikiLeaks to release the Podesta emails - though he offered conflicting accounts about how he might have done so, according to the report.

Looking for corroborating evidence, with Mr Corsi's help, prosecutors constructed a detailed timeline of Mr Corsi's emails and phone calls in that period. They sought out Mr Corsi's contacts, looking for anyone who could be a go-between to WikiLeaks.

On 3 October 2018, an FBI agent accompanied by a local sheriff's deputy knocked on the back gate of the home of James and Joanne Moriarty in the Piney Woods, a rural region of eastern Texas.

The couple had lived in Libya before the 2011 fall of ruler Muammar Gaddafi and had served as sources for Mr Corsi as he worked on articles about what he felt were the failures of the Obama administration in that country.

In the days leading up to the 7 October 2016, WikiLeaks release, they communicated several times with Mr Corsi about an article he was writing for the right-wing online outlet World Net Daily, James Moriarty told The Post.

Mr Moriarty said he and his wife greeted the FBI agent coldly, first complaining that they did not see the agent as "any kind of good person" because he had come to their home wearing a weapon under his suit jacket.

Mr Moriarty said they then spent three hours telling the agent about their experience in Libya, where he said they were detained by militants, and how they believed they had been relentlessly targeted by the US government since they returned to Texas.

"The invasion of terrorists into the United States is real and present," Mr Moriarty said. "I told him about this and I told him that, now that he knows, he has to pass it along to other government agencies, including the White House, or he will be guilty of felonious acts."

Mr Moriarty said he and his wife ultimately consented to be interviewed. The agent spoke to them separately for about 20 minutes. They both told the agent they had not connected Mr Corsi to Assange.

The dead end in the Piney Woods was typical.

Mueller report: Sarah Sanders says her untruths over FBI were told in 'heat of moment'

According to Mr Mueller's report, investigators could find "little corroboration" for Mr Corsi's claim that Stone had urged him to help spur the Mr Podesta email release.

In one interview, Mr Corsi suggested he might have publicly tweeted a message that he thought Assange would read.

"Our Office was unable to find evidence of any such tweets," Mr Mueller wrote.

Mr Gray said the frustration of the prosecution team became obvious. At one meeting, Rhee, a former partner at the prominent law firm WilmerHale, began to raise her voice as Mr Corsi insisted he clearly remembered a conversation he had with Mr Malloch a few months earlier, but not a key conversation he had shortly afterward with Mr Stone.

"That was six months ago," she said, according to Mr Gray's notes.

"We find what you're saying is lacking," Mr Zelinsky added.

By their final meeting, on 2 November 2018, the prosecutors made their concerns clear. They lectured Mr Corsi for about 20 minutes about the need to stick to definite facts.

Then they started in again: Were you a source about WikiLeaks for Roger Stone?

Mr Corsi, who had grown increasingly uncomfortable as the prosecutors spoke, had trouble answering clearly.

After about five minutes, the prosecutors declared they were done, Mr Gray said.

Mueller investigation: The key figures Show all 12 1 /12 Mueller investigation: The key figures Mueller investigation: The key figures Robert Mueller is the special counsel overseeing the investigation into Russia's meddling in the 2016 election, and potential obstruction of justice by the president. Mr Mueller has a pristine reputation in Washington, where he was previously in charge of the FBI. Throughout his investigation, he and his team have been notoriously tight lipped about what they know and where their investigation has led. REUTERS Mueller investigation: The key figures Former FBI director James Comey was the catalyst that led to the appointment of special counsel Robert Mueller. Mr Comey was fired by the president after Mr Trump reportedly asked him to drop his own Russia investigation. Mr Trump has long maintained that the investigation is a "witch hunt". AFP/Getty Images Mueller investigation: The key figures Deputy attorney general Rod Rosenstein had authority over the special counsel investigation for much of the two years it has been active. Mr Rosenstein found himself with that responsibility after then-attorney general Jeff Sessions recused himself from that oversight. AP Mueller investigation: The key figures Attorney general Jeff Sessions's decision to recuse himself from oversight of the special counsel investigation may have cost him his job in the end. Mr Sessions resigned last year, after weathering a contentious relationship with Donald Trump who vocally criticised his attorney general for taking a step back. Mr Sessions recused himself from the oversight citing longstanding Justice Department rules to not be involved in investigations overseeing campaigns that officials were apart of. AP Mueller investigation: The key figures Attorney General William Barr is currently responsible for oversight of the special counsel investigation. Mr Barr's office will be the first to receive the Mueller report when it is finished. His office will then determine what portion or version of that report should be delivered to Congress, and also made public. EPA Mueller investigation: The key figures Michal Cohn is the president's former personal lawyer, who has been helping the special counsel investigation as a part of a plea deal over financial crimes, and campaign finance crimes, he has pleaded guilty to. Among those crimes, Cohen admitted to facilitating $130,000 in hush money payments to adult film actress Stormy Daniels during the 2016 campaign. Cohen has said he did so at the direction of Mr Trump. Cohen has also admitted that he maintained contacts with Russian officials about a potential Trump real estate project in Moscow for months longer than Mr Trump and others admitted. The talks continued well into 2016 during the campaign, he has said. AP Mueller investigation: The key figures Stormy Daniels has alleged that she had an affair with Donald Trump in 2006, soon after Melania Trump gave birth to Baron Trump. The accusation is of particular importance as a result of the $130,000 hush money payment she received to keep quiet about the affair during the 2016 campaign. AP Mueller investigation: The key figures Paul Manafort was Donald Trump's former campaign chairman. Manafort was charged alongside Rick Gates for a slew of financial crimes, and was convicted on several counts in a Virginia court. He then pleaded guilty to separate charges filed in a Washington court. Manafort has been sentenced to just 7.5 years in prison for his crimes — in spite of recommendations from the special counsel's office for a much harsher sentence. AP Mueller investigation: The key figures George Papadopoulos was one of the first individuals associated with the Trump campaign to be charged by the Mueller probe. He ultimately received a 14 day prison sentence for lying to investigators about contacts he had with Russian officials. AP Mueller investigation: The key figures Roger Stone is a well known political fixer and operative, who has made a name for himself for some dirty tactics. He has been charged by the Mueller probe earlier this year, and he has been said to have had prior knowledge that WikiLeaks planned on publishing stolen emails from the Hillary Clinton campaign in 2016. Getty Images Mueller investigation: The key figures Rick Gates was charged alongside former Trump campaign chairman Paul Manafort for a range of crimes. Gates, who worked alongside Manafort for a pro-Russia Ukrainian political party. The two were charged with conspiracy and financial crimes. Gates pleaded guilty. AP Mueller investigation: The key figures Former national security adviser Michael Flynn was one of the first casualties of the Russia scandal, and was forced out of his position in the White House weeks after Donald Trump took office. Flynn pleaded guilty in 2017 to "willfully" making fraudulent statements about contacts he had with Russian officials including former Russian ambassador to the US Sergey Kislyak. Flynn then lied to Vice President Mike Pence about that contact. REUTERS

Investigation's findings

By the end, Mr Mueller's team had uncovered a wide array of contacts between Mr Trump's orbit and Russia - contradicting postelection claims from Mr Trump's representatives that there had been none.

They did not find a crime to charge.

According to the report, prosecutors concluded that Mr Page had formed relationships with Russian intelligence officials before the campaign and that he may have been targeted in 2016 by Russian officials because of his Trump campaign tie. They had trouble nailing down everything he did in Moscow during a July 2016 visit, they wrote.

But the investigation did not establish that he coordinated with the Russian effort in 2016. After the report's release, Mr Page said he was not surprised, calling his Russia interactions a "big nothingburger."

Mr Mueller's team also analysed whether Trump Jr's meeting with the Russian lawyer broke campaign finance law prohibiting foreign contributions. They determined that they would not be able to prove it did. They also said they could find no connections between the meeting and other Russian efforts to interfere in the election.

Investigators struggled to determine the motive of Manafort's contacts with Mr Kilimnik, interactions that went "very much to the heart" of the special investigation, prosecutor Andrew Weissman said in a court hearing in February.

They were hampered by not only his lies, according to the report, but his use of encrypted messaging apps. Mr Mueller ultimately did not find sufficient evidence to prove that Manafort or any other Trump associate acted as an agent of the Russian government.

Mr Stone is scheduled to go on trial in November on charges of lying to Congress, obstructing an official proceeding and witness tampering over allegations that he attempted to intimidate Mr Credico.



Key details about his case were redacted from the report because of a gag order imposed by the judge, which has also limited what Stone can say in his defence. He is, however, selling T-shirts to fund his legal defence that read, "Roger Stone did nothing wrong!"

It is not clear why Mr Mueller's team did not file the false-statement charges it threatened against Mr Corsi. Much of the report dealing with its interactions with him has also been redacted by the attorney general, who cited possible harm to an ongoing investigation. The report does not specify whether the redactions are related to Stone's case or other continuing matters.

Mr Corsi said last week that the experience showed the probe was a "fraud from the start." He said only a "criminal" would urge him to plead guilty to charges that could not be proved in court.

Mr Gray said he believes it would be inappropriate to charge Mr Corsi because he has a faulty memory and noted that prosecutors gave him extensive opportunities to amend their answers.

"They pushed and pushed," he said. "But at the end of the day, they threw up their hands and said, 'We can't use any of this.'