For nearly two years, the Trump-Russia affair dominated front pages and mired the president's administration in controversy. The inquiry, led by former FBI director Robert Mueller, focused on alleged collusion between Donald Trump's 2016 presidential campaign team and Moscow.
The final report found no evidence of a criminal conspiracy, but it detailed ten instances in which the president may have obstructed justice. Mr Mueller said the report did not exonerate Mr Trump, but he added that charging a sitting president was not an option.
During the campaign and transition, at least 17 Trump associates had contacts with Russians or WikiLeaks, according to a New York Times analysis. These included the president's son-in-law Jared Kushner, his son Donald Trump Jr, Michael Flynn, Jeff Sessions and Michael Cohen. Three associates later admitted lying about those encounters. The special counsel indicted more than 30 people, including four campaign officials and 26 Russians.
A former prosecutor, Mr Mueller served as FBI director for 12 years, with his confirmation and term extension both passing unanimously. He conducted the inquiry quietly from an unassuming office in south-west Washington, submitting his 448-page report to Attorney General William Barr on 22 March.
The report did not establish a conspiracy, but it built a substantial obstruction-of-justice case, stating: "If we had confidence after a thorough investigation of the facts that the president clearly did not commit obstruction of justice, we would so state." It also revealed that Mr Trump instructed a White House lawyer to try to remove Mr Mueller over alleged conflicts of interest; the lawyer resigned.
In addition to the special counsel inquiry, four congressional committees have been investigating Russian meddling and Trump's ties, with the Judiciary Committee issuing more than 80 document requests.
