Special Counsel John Durham testified before Congress Wednesday, fulfilling a long-held mission of Republicans to "investigate the investigators" behind the FBI's probe into potential collusion between 2016 Trump campaign and Russia.

Following the release of Special Counsel Robert Mueller's report on the matter – which concluded that there was no collusion but Russia did interfere in the election – then-Attorney General William Barr appointed Durham as special counsel to look into the origins of the FBI's investigation.

In his final report on that subject released last month, Durham stated the "FBI failed to uphold their important mission of strict fidelity to the law.

He then appeared on Capitol Hill Wednesday to explain why as well as his findings on the origins of operation "Crossfire Hurricane," the code name of the Trump-Russia investigation.

Durham characterized his team's findings in the four-year investigation as "sobering."

Those findings include that, "The FBI generally ignored the significant exculpatory information" and that it also " failed to pursue investigative leads that were inconsistent with their theory of the case." It also detailed how the agency "was willing to make use of the completely unvetted and uncorroborated Steele reporting in multiple FISA applications targeting a U.S. citizen," namely, Trump campaign Adviser Carter Page, despite knowing the findings were paid for in part by the Hillary Clinton campaign.

There is not a single substantive piece of substantive information in the dossier that has ever been corroborated," Durham said about the infamous Steele dossier.

His testimony was met with warnings from Republicans, who said that politics could also be at play with the current Trump indictment dealing with his handling of classified documents.

Rep. Jim Jordan, R-Ohio, Oversight Committee Chairman said, "Now we have an indictment of a former president who’s winning every single poll, indicted by his opponent's Justice Department."

Trump's indictment was by a federal grand jury composed of citizens who voted on bringing the 37 charges against the former president and was not an order by Pres. Joe Biden or Attorney General Merrick Garland.

Democrats meanwhile, accused Durham himself of excluding information in his report, like a Trump Tower meeting between Russian officials and Donald Trump’s son Donald Trump Jr., son-in-law Jared Kushner and then-campaign advisor, Paul Manafort, and of ultimately not recommending any wholesale changes in FBI policy, despite his findings.

"You got no convictions, you got nothing. It was all set up to hurt the Mueller report ... to hurt the Bidens and help Trump," said Rep. Steve Cohen, D-Tenn.

It is unlikely Durham will publicly discuss his report like this again, but House Republicans are expected to continue to use it as an example of what they see as a "two-tiered system of justice."