Longtime Hillary Clinton confidant Sidney Blumenthal allegedly sent her an email with the name of a CIA source, further casting doubt on her claim she never sent or received classified information on her private email address, according to the Republican chairman of the committee investigating the 2012 Benghazi attacks.

Rep. Trey Gowdy, R-S.C., provided this and other details Thursday, as part of a batch of new Clinton emails he says will shed light on Blumenthal’s complex role as unofficial political adviser to then-Secretary of State Clinton.

“It is curious Secretary Clinton took so much of her advice from someone who had never been to Libya, professed no independent knowledge of the country and who the White House blocked her from hiring,” Gowdy said in a statement Thursday.

He detailed the emails in a letter to the panel’s ranking Democrat, Maryland Rep. Elijah Cummings. He said he plans to release the emails on Oct. 12, but previewed them extensively in his letter.

At one point, Blumenthal apparently suggested President Obama back military intervention in Libya in 2011 to help boost his poll numbers; in another spate of emails, according to Gowdy, he appeared to be promoting a company run by an associate that provides training for Libya rebels. In others, he appeared to be mocking Obama and his White House advisers.

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In yet another email, Gowdy claims Blumenthal wrote to Clinton citing the name of a “human source” for the CIA. "Armed with that information," Gowdy writes, "Senator Clinton forwarded the email to a colleague -- debunking her claim that she never sent any classified information from her private email address."

One-third of the emails, according to Gowdy, are to/from Blumenthal, who was not a government employee at the time but appeared to send Clinton a steady stream of emails full of foreign policy advice before and after the U.S. intervention in Libya.

Gowdy’s email release comes at a sensitive time for the Republican-led committee. The panel has taken a drubbing in the press lately, after Majority Leader Kevin McCarthy, R-Calif., suggested in an interview with Fox News that the panel could be linked to Hillary Clinton’s dropping poll numbers, fueling Democratic claims the committee is political in nature. He later explained he “never meant to imply” that was the case.

Cummings’ office hit back on the latest salvo on Thursday, calling it “a defensive and desperate attempt to save face,” that only proves Gowdy is more focused on embarrassing Clinton than investigating the 2012 attacks on the U.S. diplomatic compound in Benghazi.

Cumming said Democrats have been asking Gowdy for weeks to release the full load of Clinton emails, as well as the entire transcript of Blumenthal’s eight-hour deposition to the committee, “in which he answered hundreds of questions form Republicans about his e-mail.”

Nevertheless, the committee is painting a more colorful picture of Blumenthal’s role as an unofficial adviser at a time when the U.S. was considering its controversial foray into Libya. A year after the government fell with the help of the U.S. and its allies, militants attacked the diplomatic compound and today Libya remains a volatile, failed state.

Gowdy says the new emails suggest Blumenthal is a “political body” who pushed for a more aggressive posture on Libya -- including sustained bombing and training and arming rebels on the ground in 2011 – to boost administration poll numbers.

From one apparent email quoted by Gowdy:  

“Obama should think about the political effect here in the U.S. of defeat of Qathafi’s forces,” Blumenthal apparently wrote of the Libyan dictator, who was eventually killed by opposition forces. “He wants to be re-elected? It would be interesting to see how his prospects would be affected by Qathafi’s continuing presence in Tripoli in November 2012 and the mockery Republicans will rain down on him over his present weakness.”

According to Gowdy, Blumenthal was a bit snarky when talking about the Obama administration, at one point reportedly writing that “[Obama] and his political cronies in the WH and Chicago are, to say the least, unenthusiastic about regime change in Libya or anywhere else in the ME. Why is that? Hmmm.”

Blumenthal also allegedly mocked “National Security Adviser Tom Donilon’s babbling rhetoric about ‘narratives’” on a phone briefing with reporters.  

Gowdy says most of Blumenthal’s shared intel on Libya came from his associates, former high-ranking CIA operative Tyler Drumheller, and Cody Shearer.

Gowdy argues the new emails also show Blumenthal had a monetary interest in seeing the U.S. intervention in Libya go forward, noting that Blumenthal and Drumheller have acknowledged their stake in Osprey Global Solutions, a private security company. But the emails tell more of the story, Gowdy says, pointing to excepts that appear to reference a deal between Osprey and the National Transition Council (TNR) in Libya.

At one point, according to a portion in the letter, Blumenthal wrote that, “Tyler, Cody and I acted as honest brokers, putting this arrangement together through a series of connections, linking the Libyans to Osprey and keeping it moving.” The arrangement, as described, was to help train and organize the opposition forces.

For her part, Clinton appeared interested in her short responses to Blumenthal, according Gowdy, often forwarding the memos to top aide Jake Sullivan and asking him to read and respond to her later. In reaction to Blumenthal’s alarms about poll numbers and Obama’s ‘present weakness’ over Libya, Clinton apparently told Sullivan: “This is quite troubling … I agree about the need to keep the attack tempo up.”

After Blumenthal was brought for a private interview with the committee in June, his lawyer James M. Cole wrote a letter to Gowdy, criticizing Republicans’ decision to leak only portions of his testimony and emails to the press.

“Leaks like these are distorting the truth by mischaracterizing facts and circumstances,” Cole wrote. “They are creating an incomplete and unfair narrative about the deposition, Mr. Blumenthal’s knowledge about Libya, and the tragedy that occurred in Benghazi.”

Cole could not be reached for comment on the letter Thursday.

FoxNews.com's Kelley Vlahos contributed to this report.