In its motion to drop the criminal charge against Mr. Flynn, the Justice Department cited Mr. Barnett’s January 2017 draft memo as evidence that there was no reason to question Mr. Flynn about his conversations with the Russian because the case was all but closed. The department also said that the F.B.I. had transcripts of Mr. Flynn’s calls with Mr. Kislyak, and there was no need, the department argued, to question him further.
Soon after the Flynn interview, Mr. Barnett asked to leave the case and said that he feared it was “problematic” enough to become the subject of an inspector general investigation, according to his interview. His request was denied.
Separately, Mr. Barr shared newly declassified information on Thursday with Mr. Graham about the primary source for the document, known as the Steele dossier after Christopher Steele, the British former spy who compiled it.
The dossier originated during the 2016 campaign as opposition research funded by Democrats. The F.B.I. included several assertions from it in applications to wiretap Carter Page, a former Trump campaign foreign policy adviser who had already been the subject of an open counterintelligence investigation before the bureau opened its Trump-Russia inquiry.
Previous declassifications by the Trump administration have resulted in the public identification of Igor Danchenko, an expert in Russian politics, as Mr. Steele’s primary source. Mr. Danchenko gathered rumors and claims from his own contacts in Russia about purported ties between Russian intelligence and Mr. Trump and his associates for it. (Mr. Danchenko has portrayed the dossier as exaggerating what he told Mr. Steele.)
The newly released information stated that Mr. Danchenko was the subject of a counterintelligence investigation from May 2009 to March 2011. That fact had been included in a previously redacted version of an inspector general report about flaws in the Page wiretap applications, and Mr. Barr provided a summary of the inquiry for Mr. Graham, who is investigating the F.B.I., to disseminate.
Mr. Barr’s summary said the investigation was opened because someone told the F.B.I. that Mr. Danchenko had made a comment at a think tank the previous year that had sounded like a solicitation to pay for unauthorized disclosures of classified information. It also said a subsequent investigation showed that Mr. Danchenko had had contact in 2005 and 2006 with people who were suspected of being Russian intelligence officers, including one at the Russian Embassy in Washington, to whom he had expressed an interest in eventually joining the country’s diplomatic service.
Mark Schamel, Mr. Danchenko’s lawyer, said in a statement on Friday: “As every objective investigation has shown, Mr. Danchenko is an exceptional analyst who is truthful and credible.”
Charlie Savage contributed reporting.