Special counsel Robert Mueller is investigating whether President Donald Trump and his campaign coordinated with Russia to help him win the 2016 presidential election — and also whether Trump tried to obstruct that investigation.
Over the past year and a half, the complex investigation has led to charges, guilty pleas, cooperation deals and prison sentences. The developments have dominated political headlines worldwide through the 2018 midterm elections and into the new Democratic control of the House of Representatives.
Here’s what you need to know about major moments in the Mueller investigation.
With The Associated Press
Mueller investigation timeline Key dates in the special counsel's probe into Russian interference in the 2016 U.S. election.
01 January 2006
Manafort and Gates begin work for a pro-Russian political party
Paul Manafort and Rick Gates begin work as consultants for a pro-Russian political party in Ukraine led by former Prime Minister Viktor Yanukovych.
07 February 2010
Yanukovych elected president of Ukraine
Viktor Yanukovych is elected president of Ukraine.
01 February 2014
Yanukovych flees Ukraine
After violent clashes between protesters and police, Yanukovych flees Ukraine and enters exile in Russia. The U.S. government later opens an investigation into Manafort’s foreign lobbying and political work.
16 June 2015
Trump announces candidacy
Donald Trump announces his candidacy for president as a Republican.
01 September 2015
FBI warns DNC about Russian hackers
The FBI contacts the Democratic National Committee’s IT help desk, cautioning that at least one computer has been compromised by Russian hackers. A technician scans the system but fails to find evidence of the intrusion.
01 March 2016
Papadopoulos meets with associates of Russian government
Manafort joins Trump campaign as a volunteer consultant. George Papadopoulos is named one of five foreign policy advisers to the campaign and meets with people associated with the Russia government amid discussions to set up a meeting between Trump and Russian President Vladimir Putin.
01 April 2016
Papadopoulos meets with Russian national offering 'dirt' on Clinton
Papadopoulos meets with Russian national who he says offered “dirt” on Democratic presidential candidate Hillary Clinton, including thousands of emails. Papadopoulos emails other members of Trump campaign about Russian offer of dirt on Clinton and offer for Trump to meet with Putin. The Democratic National Committee becomes aware of the scope of the monthslong intrusion into its email systems by hackers U.S. intelligence agencies later linked to the Russian government.
01 May 2016
Manafort is promoted to campaign chairman and chief strategist.
01 June 2016
Meeting at Trump Tower with Russian lawyer
Manafort attends a meeting at Trump Tower in Manhattan with a Russian lawyer named Natalia Veselnitskaya, who promised to provide the Trump campaign damaging information about Clinton. Donald Trump Jr. and Jared Kushner are also in the meeting. WikiLeaks founder Julian Assange says his website will publish a batch of Clinton emails.
01 July 2016
Trump gets GOP nomination
Trump becomes the Republican nominee for president. In a speech the following week, Trump encourages Russians to release hacked Clinton emails. The FBI opens an investigation into the Russian government’s attempt to influence the election, including whether members of Trump’s campaign are involved.
01 August 2016
NYT reports that Manafort’s name is on secret list
The New York Times reports that Manafort’s name appears on a secret list of payments made by the Yanukovych regime. Manafort resigns from the Trump campaign the day after The Associated Press reports he failed to register as a foreign agent after arranging a covert lobbying campaign in the United States on behalf of the Ukrainian party.
01 November 2016
Trump elected president
Donald Trump wins the presidential election.
06 January 2017
Comey briefs Trump on dossier
FBI Director James Comey, who was overseeing the ongoing investigation into Russian meddling in the 2016 presidential election, briefs Trump on contents of unverified dossier that contains salacious allegations about him and his campaign.
13 January 2017
Senate launches probe
The U.S. Senate Select Committee on Intelligence launches an investigation into Russian interference in the 2016 U.S. presidential campaign and possible links between Russia and political campaigns.
20 January 2017
Trump is inaugurated as 45th President of the United States.
25 January 2017
House announces its investigation
The House of Representatives Permanent Select Committee on Intelligence announces its own investigation.
27 January 2017
Papadopoulos interviewed by FBI
Papadopoulos is interviewed by the FBI about his contacts with Russians.
01 May 2017
Comey out, Mueller in
Trump fires Comey. Former FBI Director Robert Mueller is appointed as special counsel to take over the probe.
01 June 2017
Manafort files paperwork with DOJ
Manafort files paperwork with the Justice Department retroactively disclosing under the Foreign Agents Registration Act that his firm received more than $17 million working for the government of Ukraine between 2012 and 2014. The Washington Post reports that Mueller is investigating Trump for obstruction of justice.
01 July 2017
FBI conducts raid at Manafort’s home
FBI agents conduct a raid at former Trump campaign chairman Paul Manafort’s home in Alexandria, Virginia. Papadopoulos is arrested by the FBI at Dulles International Airport.
01 August 2017
Mueller impanels grand jury
Mueller impanels a criminal grand jury in Washington, D.C.
01 October 2017
Papadopoulos pleads guilty
Papadopoulos pleads guilty to making false statements to the FBI, as part of apparent agreement to cooperate with Mueller’s investigation. Mueller files 12-count criminal indictments against Manafort and Gates.
30 October 2017
Manafort, Gates charged
Manafort and Gates plead not guilty after their arrest on charges related to conspiracy against the United States and other felonies. The charges are the first from the special counsel investigating possible coordination between the Trump campaign and Russia.
01 December 2017
Flynn pleads guilty
Michael Flynn, the retired general who vigorously campaigned at Trump's side and then served as his first national security adviser, pleads guilty to lying to the FBI about reaching out to the Russians on Trump's behalf and says members of the president's inner circle were intimately involved with — and at times directing — his contacts. He agrees to cooperate with the special counsel's office.
20 February 2018
Prominent attorney pleads guilty
Mueller charges a prominent attorney, Alex van der Zwaan, with lying to authorities about his work with two of Trump's former campaign aides. Van der Zwaan, 33, a Dutch national, pleads guilty in federal court to charges that he lied to investigators about his conversations with Gates.
23 February 2018
Gates pleads guilty
Gates pleads guilty to federal conspiracy and false-statements charges. With his cooperation, Gates gives Mueller a witness willing to provide information on Manafort's finances and political consulting work in Ukraine — and someone who had access at the highest levels of Trump's 2016 presidential campaign.
03 April 2018
First punishment handed down
Alex van der Zwaan is sentenced to 30 days in prison in the first punishment handed down in the investigation. He was also ordered to pay a $20,000 fine.
13 July 2018
12 Russian officers charged with hacking
A Mueller indictment charges twelve Russian military intelligence officers with hacking into the Clinton presidential campaign and the Democratic Party and releasing tens of thousands of private communications in a sweeping conspiracy by the Kremlin to meddle in the 2016 election. The indictment represents Mueller's first charges against Russian government officials.
16 July 2018
Trump meets with Putin
Trump meets with Putin in Helsinki, Finland. Trump says Putin made an "incredible offer" to help American investigators in their prosecution of the 12 Russian intelligence officers.
21 August 2018
Manafort found guilty
Manafort is found guilty of eight financial crimes in the first trial victory of the special counsel investigation into the president's associates. A judge declares a mistrial on 10 other counts the jury could not agree on.
14 September 2018
Manafort agrees to cooperate
Manafort agrees to cooperate with Mueller's investigation as he pleads guilty to federal crimes and avoids a second trial that could have exposed him to more time in prison. Manafort pleaded guilty to two charges of conspiracy in relation to his lobbying work with pro-Russian groups in Ukraine.
10 October 2018
California man sentenced to prison
Richard Pinedo, a California man who pleaded guilty in February 2018 to unwittingly helping the Russian election disruption efforts by trading in stolen identifications and bank account numbers, is sentenced to 6 months in prison.
06 November 2018
Democrats retake the House
Democrats retake the U.S. House of Representatives in midterm elections, gaining control of key investigatory committees.
07 November 2018
Attorney General Jeff Sessions resigns as the country's chief law enforcement officer at Trump's request. Sessions announced his plan to resign in a letter to the White House, the day after the midterm election. Trump announces in a tweet that Sessions' chief of staff Matt Whitaker would become the new acting attorney general with authority to oversee the remainder of Mueller's investigation.
16 November 2018
Trump cooperates with the investigation
Trump says he has finished his answers to questions posed by Mueller. He says four days later that he has provided them to the special counsel, the first time he has directly cooperated.
23 November 2018
Corsi reportedly in plea talks with Mueller's team
Jerome Corsi, a conservative writer and associate of Trump confidant Roger Stone, tells The Associated Press that he is in plea talks with Mueller’s team. Mueller’s team questioned Corsi as part of an investigation into Stone’s connections with WikiLeaks.
26 November 2018
Mueller accuses Manafort of violating plea agreement
Mueller accuses Manafort of violating his plea agreement by repeatedly lying to federal investigators, an extraordinary allegation that could expose him to a lengthier prison sentence and potentially more criminal charges. Papadopoulos begins serving his two-week prison sentence after a judge rejects his last-minute bid to remain free.
29 November 2018
Cohen confesses in an unexpected guilty plea that he lied to Congress in 2017 out of “loyalty” to Trump about a project his company tried to develop in Moscow in 2016 as he ran for president. Cohen says he falsely claimed that talks about the project ended in January 2016, when they in fact continued until that June.
03 December 2018
Trump weighs in on Cohen
Trump calls for a "full and complete" sentence for Cohen.
04 December 2018
Prosecutors speak out on Flynn's cooperation
Prosecutors say Flynn provided so much information to the investigation that he shouldn't do any prison time.
07 December 2018
Court filings reveal contact between Trump associates, Russian intermediaries
Federal prosecutors urge a "substantial" prison term for Cohen. Court filings from New York prosecutors and Mueller’s office reveal for the first time contacts between Trump associates and Russian intermediaries, with Cohen described as being in touch with a Russian offering "political synergy" as far back as 2015. In describing how Manafort breached a plea agreement, Mueller says Manafort told "multiple discernible lies" to prosecutors about his contacts with the Trump administration and an associate with alleged ties to Russian intelligence. Papadopolous is released from jail after serving a two-week sentence.
12 December 2018
Cohen sentenced to prison
Cohen is sentenced to 3 years in prison in federal court in Manhattan for crimes that included efforts to hide the president's Russia business dealings and alleged extramarital affairs with a porn star and a model. U.S. District Judge William H. Pauley III's sentence dashed Cohen's bid to avoid prison by aiding federal prosecutors and Mueller. Cohen accused Trump of directing hush-money payments to the two women that violated election laws. Cohen also pleaded guilty to tax and bank fraud charges and lying to Congress. "While Mr. Cohen has taken steps to mitigate his criminal conduct ... that does not wipe the slate clean," said Pauley, blasting Cohen's "greed and ambition" and the "insidious harm" he inflicted on democratic institutions. The judge also ordered a $100,000 fine and a March 6 surrender. Cohen, in an emotional statement before the judge sentenced him, apologized to his family and denounced Trump for inspiring "blind loyalty" that led down a "path of darkness over light."
18 December 2018
Flynn's sentencing delayed
A federal judge sharply rebukes Flynn and unexpectedly delays sentencing him after warning he could go to prison for lying to the FBI about his contacts with the Russian ambassador. Prosecutors from Mueller's team had recommended leniency.
20 December 2018
AP: Whitaker chose not to recuse himself from probe
A senior official tells The Associated Press that Whitaker chose not to recuse himself from the Russia investigation even though a top Justice Department ethics official advised him to step aside out of an "abundance of caution."
04 January 2019
Grand jury's term extended
The chief federal judge in Washington extends the term of the grand jury used by Mueller, a sign that the probe will continue for at least several months.
08 January 2019
Filing reveals Manafort shared polling data
A defense filing inadvertently reveals that Manafort shared polling data during the 2016 presidential campaign with Konstantin Kilimnik, a Russian-Ukrainian business associate accused of having ties to Russian intelligence, and prosecutors say he lied to them about it. It is the first time that prosecutors with Mueller’s office have accused Trump’s chief campaign aide of sharing election-related information with his Russian contacts.
09 January 2019
AP: Rosenstein expected to leave
A person familiar with the plans tells The Associated Press that Rod Rosenstein is expected to leave his position soon after William Barr, Trump’s nominee for attorney general, is confirmed.
10 January 2019
Cohen says he will testify before House committee
Cohen says he will testify publicly before the House Oversight and Reform Committee, newly led by Democrats, on Feb. 7.
11 January 2019
NYT reports FBI began investigating Trump
The New York Times reports that FBI officials began investigating whether Trump "had been working on behalf of Russia against American interests" after he fired Comey. Mueller took over the investigation, and it is unclear whether Mueller is still investigating that, The Times reported.
12 January 2019
Washington Post: Trump concealed details of Putin talks
The Washington Post reports that Trump concealed details of his conversations with Putin, including taking the notes of an interpreter.
15 January 2019
Barr's confirmation hearing
Barr appears before the Senate Judiciary Committee for his confirmation hearing. He says he doesn’t believe Mueller "would be involved in a witch hunt."
18 January 2019
Mueller’s office responds to BuzzFeed News report
Mueller’s office issues a rare public statement disputing the accuracy of a BuzzFeed News report that said Cohen told Mueller that the president directed him to lie to Congress. BuzzFeed, citing two unidentified law enforcement officials, reported that Trump directed Cohen to lie to Congress about a Moscow real estate project and that Cohen told Mueller the president personally instructed him to lie about the timing of the deal. The report said Mueller’s investigators learned about Trump’s directive “through interviews with multiple witnesses from the Trump Organization and internal company emails, text messages, and a cache of other documents.” Mueller's office does not cite specific errors, but the special counsel’s spokesman, Peter Carr, says, “BuzzFeed’s description of specific statements to the special counsel’s office, and characterization of documents and testimony obtained by this office, regarding Michael Cohen’s congressional testimony are not accurate.”
23 January 2019
Cohen postpones testimony to Congress
Cohen postpones his testimony to Congress, citing threats Trump made against his family "due to ongoing threats against his family from President Trump and Giuliani," Cohen's spokesman says.
25 January 2019
FBI arrests Roger Stone
Roger Stone, a longtime Trump adviser, is arrested by the FBI in a predawn raid at his Florida home on several criminal charges stemming from Mueller's investigation. Stone is charged in a seven-count indictment with witness tampering, obstruction and false statements about his interactions related to the release by WikiLeaks of hacked emails during the 2016 presidential election. Some of those false statements were made to the House intelligence committee, according to the indictment. Stone had said for months that he was prepared to be charged, though he denied any wrongdoing.
28 January 2019
The investigation is 'close to being completed'
Whitaker says of Mueller's probe, "The investigation is, I think, close to being completed," at an unrelated news conference. He says he has been "fully briefed," but does not elaborate or give any timetable. Cohen agrees to talk to the House Intelligence Committee on Feb. 8 in closed-door testimony.
04 February 2019
Subpoena for documents from Trump’s inaugural committee
The U.S. Attorney’s Office in Manhattan issues a subpoena seeking documents from Trump’s inaugural committee.
05 February 2019
Trump's State of the Union
In his State of the Union address, Trump takes aim at Mueller's Russia probe and a series of other investigations House Democrats have promised, labeling them "ridiculous partisan investigations."
08 February 2019
National Enquirer secretly assisted Trump’s campaign
Two people tell The Associated Press that federal prosecutors are looking into the National Enquirer's handling of a story about Amazon CEO Jeff Bezos' extramarital affair to see if the tabloid's publisher violated a cooperation agreement with prosecutors. The tabloid acknowledged secretly assisting Trump’s White House campaign by paying $150,000 to Playboy centerfold Karen McDougal for the rights to her story about an alleged affair with Trump. The company then buried the story until after the 2016 election. Cohen pleaded guilty to charges that included helping to broker that transaction.
11 February 2019
Cohen delays testimony
Cohen again delays his testimony.
13 February 2019
Judge rules Manafort intentionally lied
A district judge rules that Manafort intentionally lied to investigators and a federal grand jury in the Mueller investigation. The four-page ruling hurts Manafort’s chance of receiving a reduced sentence. The ruling was largely a rejection of Manafort’s attorneys’ argument that he hadn’t intentionally misled investigators about his interactions with Kilimnik but rather forgot some details until his memory was refreshed.