NEW YORK (BLOOMBERG) - Special Counsel Robert Mueller's investigation into whether President Donald Trump's campaign colluded with Russia has reached deep into the White House with the guilty plea of former National Security Adviser Michael Flynn, who is cooperating in the widening probe.
For months, Mr Mueller's investigators have been piecing together details of in-person meetings, phone calls, e-mails and other communication between members of Mr Trump's inner circle and the Russian government, both during the campaign and after Mr Trump's election victory.
With Mr Flynn's guilty plea, facts uncovered by Mr Mueller are being made public and can be put into context with other details. Here are some of the key events since Election Day.
Early December 2016: Mr Trump's son-in-law and senior White House adviser Jared Kushner meets Russian Ambassador Sergey Kislyak at Trump Tower to discuss setting up a secure channel for communications between Russia and the transition team. Flynn attends the meeting.
Dec 21: Egypt submits to the UN Security Council a resolution about Israeli settlements. The Security Council is scheduled to vote the next day.
Dec 22: A very senior member of the transition team (later identified as Mr Kushner) directs Mr Flynn to contact foreign governments including Russia to learn where each government stands on the resolution and to influence those governments to delay the vote or defeat the resolution.
Dec 22: Flynn contacts Mr Kislyak about the vote. Flynn tells him about the Trump administration's opposition to the resolution and requests that Russia vote against or delay the resolution. The Security Council adopts the resolution with 14 votes and the US abstaining on Dec 23.
Dec 23: Flynn again speaks to Mr Kislyak, who informs Flynn that if it comes to a vote, Russia would not vote against the resolution.
Dec 28: President Barack Obama signs an order to take effect the next day implementing sanctions against Russia for its interference in the 2016 election.
Dec 28: Mr Kislyak contacts Flynn.
Dec 29: Flynn calls a senior official of the Trump transition team - reportedly Ms K.T. McFarland - to discuss what to tell Mr Kislyak. Ms McFarland, who was with other senior members of the transition team at Mr Trump's Mar-a-Lago resort, discusses the sanctions with Flynn, and tells him that other members of the transition team don't want to escalate the situation.
Dec 29: After the call, Flynn calls and asks that Russia not escalate the situation and only respond in a reciprocal manner.
Dec 29: Flynn speaks with Ms McFarland to report on his call with Mr Kislyak, including their discussion of sanctions.
Dec 30: Russian President Vladimir Putin releases a statement saying his nation wouldn't take retaliatory measures for US sanctions.
Dec 30: At 2.41pm, Mr Trump tweets: "Great move to delay (by V. Putin) - I always knew he was very smart!"
Dec 31: Mr Kislyak calls Flynn and tells him that Russia has chosen not to retaliate in response to Flynn's request.
Dec 31: After the call, Flynn speaks with senior members of the transition team about his conversations with Mr Kislyak over sanctions and Russia's decision not to escalate.
Jan 20, 2017: Mr Trump is sworn in as 45th president of the US.
Jan 24: On his second day in his job as National Security Adviser, Flynn agrees to be interviewed by FBI agents. He tells them he didn't ask Mr Kislyak to refrain from escalating the response to sanctions. He also says he didn't recall a follow-up conversation in which Mr Kislyak said Russia would moderate its response. Both statements are later proved false.
Flynn also deceives agents about calls he made to Russia and other countries about the Egypt resolution. He tells them that he asked only about the countries' positions on the vote and didn't ask that any country take particular actions. He says that he never described Russia's response to him. Both statements are lies.
Jan 26: Acting Attorney-General Sally Yates warns White House counsel Don McGahn that Flynn was lying about his calls with Mr Kisylak and that it made him vulnerable to blackmail by Russia.
Jan 27: Mr Trump asks FBI director Jim Comey for a pledge of loyalty over a private dinner at the White House. Mr Comey declines to make the pledge.
Jan 27: George Papadopoulos, a volunteer foreign policy adviser to the Trump campaign, lies to the FBI about his contacts with people tied to the Russian government during the 2016 campaign.
Jan 30: Ms Yates is fired by Mr Trump for her refusal to defend a travel ban.
Feb 13: Flynn resigns after press reports that he misled Vice-President Mike Pence and other top White House officials about his contacts with Mr Kislyak.
Feb 14: Mr Trump asks Mr Comey to drop the probe into Flynn, saying: "I hope you can see your way clear to letting this go, to letting Flynn go. He is a good guy. I hope you can let this go." Mr Trump denies making the request.
March 2: Attorney-General Jeff Sessions, who previously served as a Trump campaign adviser, recuses himself from any investigation into Russia's meddling in the election, after reports disclosed his contacts in 2016 with Mr Kisylak.
March 7: Flynn files documents with the Justice Department under the Foreign Agents Registration Act about a project performed by him and his company, the Flynn Intel Group Inc. Flynn lies in several statements, including that his company didn't know whether Turkey was involved in the project, that the project was focused on improving US companies' confidence in doing business in Turkey, and that Flynn alone wrote an op-ed in the Hill on election day. He omits that officials from Turkey supervised and directed what he wrote.
March 31: Mr Trump tweets that "Mike Flynn should ask for immunity in that this is a witch hunt (excuse the big election loss), by media & Dems, of historic proportion!"
May 9: Mr Trump fires Mr Comey as FBI director, purportedly acting on a recommendation from Mr Sessions and Deputy Attorney-General Rod Rosenstein, who cited his handling of the Hillary Clinton e-mail investigation. Mr Trump subsequently provides other reasons for Mr Comey's firing.
May 10: Mr Trump tells Russian officials meeting him in the Oval Office that firing Mr Comey had relieved "great pressure" on him.
May 17: Mr Robert Mueller is appointed special counsel by Acting Attorney Rod Rosenstein.
July 8: News reports disclose a June 2016 meeting at Trump Tower involving Mr Kushner, Trump campaign manager Paul Manafort, Mr Donald Trump Jr and Russians with links to the Kremlin.
Oct 5: Papadopoulos pleads guilty to lying to the FBI. He admits that he lied about contacts with Russians who said they could provide "dirt" on Mrs Clinton in the form of thousands of e-mails. The case is unsealed on Oct 30.
Mid-October: Mr Mueller serves Mr Trump's election campaign with a subpoena for documents related to any contacts with Russian operatives. On the same day the subpoenas are disclosed.
Nov 16: Top lawmakers on the Senate Judiciary Commission press Mr Kushner to provide additional documents because he failed to previously provide all documents requested.
Oct 27: Manafort is indicted on fraud charges related to his earlier business transactions. His deputy Rick Gates is also charged. They deny wrongdoing after the case is unsealed on Oct 30.
November: Mr Kushner reportedly meets with Mr Mueller's team and is asked about Flynn.
Dec 1: Flynn pleads guilty to lying to the FBI and agrees to cooperate with Mueller. Mr Kushner is referred to in Flynn's statement of facts as the "very senior" transition official and Ms McFarland as the "senior" official.
