Former secretary of state Hillary Clinton testifies before the House Select Committee on Benghazi in Washington on Oct. 22, 2015. (Melina Mara/The Washington Post)

A group of about 30 emails sent or received by Hillary Clinton about the 2012 Benghazi, Libya, attacks and recovered in an FBI investigation into her use of a private email system contains only one previously undisclosed email, government lawyers said in a filing Wednesday.

The revelation of the existence of as many as 30 potentially related emails in a conservative group’s public records lawsuit briefly roiled the presidential race on Aug. 30, triggering attacks by Republican presidential nominee Donald Trump’s campaign. But the criticisms were undercut by the single newly released email, which is a complimentary note to Clinton from another U.S. diplomat.

In the message, dated Jan. 23, 2013, the U.S. ambassador to Brazil at the time, Thomas Shannon, praised the then-secretary of state’s Senate testimony about the September 2012 attacks that killed ambassador J. Christopher Stevens and three other Americans.

“I watched with great admiration as she dealt with a tough and personally painful issue in a fair, candid and determined manner,” Shannon wrote Clinton’s then-chief of staff Cheryl D. Mills, who forwarded the note to Clinton. “I was especially impressed by her ability to turn aside the obvious efforts to politicize the events in Benghazi, reminding Americans of the tremendous sacrifice made by Chris Stevens and his colleagues but also insisting that our ability to play a positive role in the world and protect U.S. interests requires a willingness to take risks.”

Democratic presidential candidate Hillary Clinton on Capitol Hill on Oct. 22, 2015. (Jonathan Ernst/Reuters)

The government said in a filing that all the other emails turned out to be unrelated or duplicates of previously searched records.

In a statement about the newly disclosed email, State Department spokesman Mark Toner said, “The email does not change the facts that have previously been made clear about the Benghazi attacks.”

Toner said two other documents are near duplicates of emails returned to the department by Clinton in December 2014, after her tenure as secretary from 2009 to 2013, that Clinton directed assistants to print out. One was an end-of-year 2012 message to department staffers, and the other was a complimentary message by a former campaign staffer, Rick Jasculca.

“As we suspected, it appears these emails were almost entirely redundant with ones she had produced previously,” Clinton campaign spokesman Brian Fallon said.

In a statement, Judicial Watch, the conservative group that has sued for Benghazi-related records, objected to the government’s withholding of what it called “printed internal technical metadata” on the two FBI-retrieved documents that were not included in a set of about 30,000 emails that Clinton’s lawyers previously deemed work-related and that she had returned to the State Department.

The Justice Department closed the email investigation without criminal charges on July 7, and FBI Director James B. Comey said investigators did not believe emails on the private server were intentionally deleted in an effort to conceal them, but purged through normal processes.

The bureau has turned over 14,900 recovered documents to the State Department for review and potential release.

Judicial Watch filed a civil public records lawsuit over the records.