He didn't want to be there, but former special counsel Robert Mueller appeared before Congress on Wednesday.

Mueller testified about his recently completed investigation into Russian election interference. It was just the second time in two years that he is spoke publicly.

In May, Mueller delivered a statement saying that his office's written work "speaks for itself" and that "the report is my testimony." But Congress subpoenaed him anyway, and he testified Wednesday before the House Judiciary Committee and the House Intelligence Committee.

Mueller was appointed to oversee the investigation into Russian interference in the 2016 election, including potential collusion between Donald Trump's campaign associates and Russian officials. Mueller's team also investigated whether Trump obstructed justice.

"My staff and I carried out this assignment with that critical objective in mind: to work quietly, thoroughly, and with integrity so that the public would have full confidence in the outcome," he said in his opening statement Wednesday to the House Judiciary Committee.

Mueller emphasized three points in that statement: that the Russian government interfered in the election "in sweeping and systematic fashion"; that his investigation did not establish that members of the Trump campaign conspired with the Russian government to interfere; and that "based on Justice Department policy and principles of fairness," his office decided that it would not make a determination on whether Trump committed a crime.

Mueller arrives to testify before the House Intelligence Committee. It was his second of two hearings on Wednesday.
Mueller arrives to testify before the House Intelligence Committee. It was his second of two hearings on Wednesday.
Saul Loeb/AFP/Getty Images
Mueller has decades of experience testifying before Congress. But the last time he did it was more than six years ago, during his final weeks serving as FBI director.
Mueller has decades of experience testifying before Congress. But the last time he did it was more than six years ago, during his final weeks serving as FBI director.
Leah Millis/Reuters
House Intelligence Committee Chairman Adam Schiff, left, talks with US Rep. Devin Nunes, the ranking member of the committee, before Mueller's second hearing of the day. Both congressmen are from California. Schiff is a Democrat, and Nunes is a Republican.
House Intelligence Committee Chairman Adam Schiff, left, talks with US Rep. Devin Nunes, the ranking member of the committee, before Mueller's second hearing of the day. Both congressmen are from California. Schiff is a Democrat, and Nunes is a Republican.
Alex Brandon/AP
A binder reading "Vol 2. Obstruction" sits on a table prior to Mueller's second hearing Wednesday.
A binder reading "Vol 2. Obstruction" sits on a table prior to Mueller's second hearing Wednesday.
Chip Somodevilla/Getty Images
A quote from Mueller's report appears behind him during his testimony Wednesday.
A quote from Mueller's report appears behind him during his testimony Wednesday.
Saul Loeb/AFP/Getty Images
House Judiciary Committee Chairman Jerrold Nadler, left, listens to Mueller's testimony on Wednesday. The New York Democrat is joined at right by US Rep. Doug Collins, the ranking member of the committee and a Republican from Georgia.
House Judiciary Committee Chairman Jerrold Nadler, left, listens to Mueller's testimony on Wednesday. The New York Democrat is joined at right by US Rep. Doug Collins, the ranking member of the committee and a Republican from Georgia.
Alex Brandon/AP
Mueller checks a binder during his testimony. As he fielded questions from both Democrats and Republicans, Mueller <a href="index.php?page=&url=https%3A%2F%2Fwww.cnn.com%2F2019%2F07%2F24%2Fpolitics%2Fmueller-testimony-before-congress%2Findex.html" target="_blank">said little in stutter-step exchanges,</a> frequently referring lawmakers back to the report and asking for questions to be repeated. He declined to engage on the question of impeachment or efforts to criticize his investigation and report.
Mueller checks a binder during his testimony. As he fielded questions from both Democrats and Republicans, Mueller said little in stutter-step exchanges, frequently referring lawmakers back to the report and asking for questions to be repeated. He declined to engage on the question of impeachment or efforts to criticize his investigation and report.
Alex Brandon/AP
US Rep. Jim Jordan, a Republican from Ohio, questions Mueller during the first hearing on Wednesday. Democrats walked Mueller through the key passages of his report, while Republicans sought to undercut the investigation, raising questions about his decision to write a lengthy report about the President's conduct when he did not decide to prosecute Trump on obstruction of justice.
US Rep. Jim Jordan, a Republican from Ohio, questions Mueller during the first hearing on Wednesday. Democrats walked Mueller through the key passages of his report, while Republicans sought to undercut the investigation, raising questions about his decision to write a lengthy report about the President's conduct when he did not decide to prosecute Trump on obstruction of justice.
Chip Somodevilla/Getty Images
"It is unusual for a prosecutor to testify about a criminal investigation, and given my role as a prosecutor, there are reasons why my testimony will necessarily be limited," Mueller said in his opening statement to the House Judiciary Committee.
"It is unusual for a prosecutor to testify about a criminal investigation, and given my role as a prosecutor, there are reasons why my testimony will necessarily be limited," Mueller said in his opening statement to the House Judiciary Committee.
Stephen Voss for CNN
Mueller testifies before the House Judiciary Committee on Wednesday.
Mueller testifies before the House Judiciary Committee on Wednesday.
Stephen Voss for CNN
Former Deputy Special Counsel Aaron Zebley looks on during the first hearing Wednesday.
Former Deputy Special Counsel Aaron Zebley looks on during the first hearing Wednesday.
Stephen Voss for CNN
Mueller is photographed after he arrived on Capitol Hill for testimony.
Mueller is photographed after he arrived on Capitol Hill for testimony.
Chip Somodevilla/Getty Images
A woman holds a copy of the Mueller Report during Wednesday's testimony before the House Judiciary Committee.
A woman holds a copy of the Mueller Report during Wednesday's testimony before the House Judiciary Committee.
Chip Somodevilla/Getty Images
Mueller and former Deputy Special Counsel Aaron Zebley are sworn in before the House Intelligence Committee. Zebley was responsible for the day-to-day oversight of the investigation, Mueller said.
Mueller and former Deputy Special Counsel Aaron Zebley are sworn in before the House Intelligence Committee. Zebley was responsible for the day-to-day oversight of the investigation, Mueller said.
Stephen Voss for CNN
Televisions show the proceedings at Duffy's Irish Pub, a Washington bar that was having a Mueller watch party on Wednesday.
Televisions show the proceedings at Duffy's Irish Pub, a Washington bar that was having a Mueller watch party on Wednesday.
Alex Wroblewski/Getty Images
Mueller arrives at the Rayburn House Office Building in Washington.
Mueller arrives at the Rayburn House Office Building in Washington.
Stephen Voss for CNN
Congressional staff talk in the hearing room of the Rayburn House Office Building.
Congressional staff talk in the hearing room of the Rayburn House Office Building.
Stephen Voss for CNN
People wait outside the hearing room at the Rayburn House Office Building.
People wait outside the hearing room at the Rayburn House Office Building.
Stephen Voss for CNN
Mueller arrives on Capitol Hill.
Mueller arrives on Capitol Hill.
Stephen Voss for CNN
Posters of Mueller are seen outside a construction site in Washington.
Posters of Mueller are seen outside a construction site in Washington.
Stephen Voss for CNN
People wait outside the Rayburn House Office Building.
People wait outside the Rayburn House Office Building.
Stephen Voss for CNN
The exterior of the Rayburn House Office Building.
The exterior of the Rayburn House Office Building.
Stephen Voss for CNN
The US Capitol at sunrise on Wednesday.
The US Capitol at sunrise on Wednesday.
Stephen Voss for CNN