The Justice Department has opened an investigation into the origins of its own probe into the 2016 election and Russian interference. The criminal inquiry, launched by Attorney General William Barr, seeks to figure out how the probe into Russian interference and collusion “all began.”

Former special counsel Robert Mueller closed the investigation months ago, after publishing a report on his findings.

Although the Mueller Report established that Russia did meddle in the U.S. election, Mueller did not find enough evidence to directly link President Donald Trump to the efforts. He wrote, “While this report does not conclude that the President committed a crime, it also does not exonerate him.”

Barr had opened an administrative review of how the department handled the investigation, but the upgrade to a criminal inquiry means officials could face criminal charges because of their work. It allows John Durham, the attorney leading the probe, to subpoena witnesses and documents and assemble a grand jury.

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When it was just an administrative review, Durham could only voluntarily interview witnesses and investigate government documents.

Trump will likely celebrate the news, as he has previously accused the Obama administration, FBI officials and Mueller of “treason” for investigating Russian collusion. Critics of the president worry that this investigation will provide a direct pathway for him to go after his political opponents.

Durham has questioned over 24 current and former officials to see if political bias against the president motivated the Russia investigation.

It is unclear what criminal charges could be brought against the investigators, but former officials speculated to Politico that Barr may believe someone deliberately gave a false testimony or
or “intentionally introduced inaccurate information during the Foreign Intelligence Surveillance Act process.”

The chairman of the House Judiciary Committee, Jerry Nadler (D-New York), and the chairman of the House Intelligence Committee, Adam Schiff (D-California), issued a joint statement Thursday voicing concern that the investigation will be used as political payback by the president. The two men are also part of a group of representatives leading the impeachment inquiry into Trump.

“These reports, if true, raise profound new concerns that the Department of Justice under Attorney General William Barr has lost its independence and become a vehicle for President Trump’s political revenge,” they said. “If the Department of Justice may be used as a tool of political retribution, or to help the President with a political narrative for the next election, the rule of law will suffer new and irreparable damage.”