The contents of Mueller’s report were not immediately made public, but Barr said in a letter to members of Congress that he was “committed to as much transparency as possible.”
Over the course of the investigation, which began in May 2017 after Trump fired FBI Director James Comey, Mueller’s team has been involved in indicting 34 people and three Russian companies.
In July 2018, the special counsel indicted 12 Russian intelligence officers in connection with hacking the Democratic National Committee and Hillary Clinton’s presidential campaign in the months before the 2016 election.
Within Trump’s inner circle, Mueller secured convictions or guilty pleas from former campaign chairman Paul Manafort, former campaign deputy Rick Gates, former campaign aide George Papadopoulos, former national security adviser Michael Flynn and former Trump personal lawyer and fixer Michael Cohen.
Cohen was sentenced in December to three years in prison for a variety of crimes, including campaign finance violations related to paying women hush money to keep them quiet about alleged sexual affairs with Trump.
This article has been updated with information about the investigation and indictments so far.