The Justice Department has released a pair of documents casting fresh doubt on the judgment of senior law enforcement officials who investigated possible links between Russia and the Trump campaign in 2016, showing that one of the FBI case agents thought prosecutors were out to “get Trump” and that a key source of allegations against the president had been previously investigated as a possible Russian asset.

The disclosures come as President Trump and his allies await the results of an investigation by Connecticut U.S. Attorney John Durham into how U.S. intelligence agencies examined Russian election interference four years ago. Instead, Thursday night saw one disclosure made to Congress and another made to the courts.

It’s still uncertain whether Durham will issue any findings before Election Day, but the two releases may serve a similar purpose: providing fresh ammunition for conservatives’ arguments that the FBI’s pursuit of the president was unfair and unfounded.

In a letter to Senate Judiciary Committee Chairman Lindsey O. Graham (R-S.C.), Attorney General William P. Barr said the individual whose information was used to assemble much of a dossier of allegations against the Trump campaign had been the subject of a national security investigation between 2009 and 2011, because FBI agents suspected he might be working for Russia.

The individual’s identity has been kept secret for years, but people familiar with the case said it is Igor Danchenko, a lawyer born in Ukraine who worked at a Washington think tank when he came under suspicion by the FBI for his Russian contacts. Danchenko’s lawyer has acknowledged he was a source of Christopher Steele’s.

In 2016, Danchenko took an assignment from Steele, a British former intelligence officer, to gather information about Trump’s dealings with Russia; Steele later wrote reports that claimed Trump and a number of his close advisers were colluding with Russia. Those reports were based in large part on a person Steele called his “primary sub-source,” which was Danchenko, according to people familiar with the matter, who spoke on the condition of anonymity to elaborate on statements in official documents.

Although Steele’s allegations were not relied on as a basis to open the investigation into Trump’s campaign, they were used to justify secret surveillance on a former Trump campaign adviser, Carter Page. The Justice Department’s inspector general, Michael Horowitz, later found the court applications for that surveillance were riddled with serious errors and omissions.

Republicans quickly seized on the details of the FBI’s old suspicions of Danchenko.

In a statement, Graham said the “failure of the FBI to inform the court that the Primary Sub-source was suspected of being a Russian agent is a breach of every duty owed by law enforcement to the judicial system” and a “small group of individuals” in the FBI and Justice Department should be held accountable for their handling of the case.

The senator, a prominent supporter of Trump, did not identify those officials, but a part of his committee’s reexamination of the 2016 probe has focused intently on former FBI director James B. Comey and his deputy, Andrew McCabe.

An FBI spokesperson declined to comment.

Danchenko’s lawyer, Mark Schamel, said: “As every objective investigation has shown, Mr. Danchenko is an exceptional analyst who is truthful and credible.”

Separately, the Justice Department filed a new document in the court fight over the conviction of former national security adviser Michael Flynn. Flynn pleaded guilty in 2017 to lying to the FBI about his conversations with a Russian ambassador; he later decided to fight the case, and the Justice Department has asked a judge to toss out the conviction, a move that angered some current and former federal prosecutors over what they say is political favoritism for a friend of the president.

Shortly before midnight Friday, prosecutors filed a summary of an interview conducted last week with FBI agent William Barnett, in which the veteran agent assigned to the Flynn case and the office of special counsel Robert S. Mueller III criticized what he called a “get Trump” attitude by some on Mueller’s team.

Barnett said he believed Flynn’s motive for lying to FBI agents about his contacts with Russia’s ambassador was to save his job, rather than to cover up collusion between the Trump campaign and Russia.

The agent said the investigative steps they took were “legally justified” and he felt there was good reason to scrutinize other Trump advisers, but too often Mueller’s team appeared to be pursuing a theory of Russian-Trump campaign collusion built on “supposition upon supposition.”

In a 476-page report issued last year, Horowitz found there was not evidence that political bias affected decisions in the investigation.

It is not unusual for federal agents and prosecutors to disagree about the nature of an investigation or the best course of action, but it is incredibly rare for those differences to be aired out in public court documents.

The disclosure comes four days before U.S. District Judge Emmet G. Sullivan is set to hear arguments over whether to dismiss Flynn’s case, and the Justice Department now cites Barnett’s statements as evidence of the “frail and shifting justifications” for the investigation and the “irregular procedure” of Flynn’s FBI interview.

Barnett’s voluntary interview was conducted last week as part of a review of the Flynn case by Jeff Jensen, the U.S. attorney handpicked by Barr to reexamine the case.

The agent said he thought the Trump campaign may have been aware the Russians were attempting to interfere in the election, but that was different from their having an explicit deal or a quid pro quo, according to the interview notes.

Barnett said he believed prosecutors pursued a Trump-Russia conspiracy theory without much evidence to go on. He even joked with others about playing a hypothetical game of “Collusion Clue,” based on the popular board game, in which they would propose different people and locations for the scene of the supposed crime.

In his interview, Barnett was particularly critical of Jeannie Rhee, a prosecutor on Mueller’s team. He said that in one briefing, she wanted to “drill down” on the fees Flynn was paid for a speech in Russia, and seemed dismissive of Barnett’s assessment that there were logical reasons for the payments, according to the court documents released this week. Barnett alleged that Rhee seemed “obsessed” with Flynn and that she “had an agenda,” the documents say, without specifying what that agenda was.

A person familiar with the Russia investigation said the briefing was a very early attempt to get special counsel prosecutors up to speed on the existing Flynn investigation. Ultimately, Rhee was assigned to a separate probe — the investigation of possible coordination between the Trump campaign and Russia.

The person familiar with the matter, speaking on the condition of anonymity because of the matter’s political sensitivity, said Rhee and Barnett worked on different pieces of the investigation and had few interactions.

A Mueller representative declined to comment.