President Donald Trump speaks to the press before boarding Marine One as he departs from the South Lawn of the White House in Washington, March 22, 2019.

Attorney General William Barr said Sunday that special counsel Robert Mueller's Russia investigation did not find sufficient evidence to establish that President Donald Trump committed obstruction of justice, or that the president's campaign coordinated with Moscow's efforts to influence the 2016 election.

In a four-page letter to top lawmakers, the top Justice Department official summarized key findings from Mueller's historic investigation. The probe, which ended as Mueller submitted his final report to Barr on Friday, has dogged the Trump administration and gripped the nation for nearly two years. Barr had the authority to decide what information to share with both Congress and the public, including whether they will see Mueller's full report.