A top State Department official who oversaw record-keeping under Hillary Clinton frequently communicated with the former secretary of state on her private email address, but his agency denies he knew Clinton relied on a private email network.

Patrick Kennedy, the State Department's undersecretary for management, has caught the attention of government watchdogs given his deep involvement in the most controversial aspects of Clinton's tenure, from Benghazi to her private emails.

David Bossie, president of Citizens United, said his group has received a number of emails through the Freedom of Information Act that show Kennedy exchanged diplomatic information with Clinton using her private email address.

"For him to have told Congress that he was not aware is just simply a lie," Bossie told the Washington Examiner. "Undersecretary Kennedy needs to be held to account and it really brings it to the question of congressional oversight."

Benghazi committee staff have declined to characterize Kennedy's Feb. 3 testimony in which Kennedy reportedly denied knowing the scope of Clinton's private email use.

Like other administration officials caught exchanging messages with Clinton on her personal server, Kennedy may have argued he did not realize Clinton used a private account exclusively for all of her work-related communications.

Bossie said the House Oversight and Government Reform Committee should be permitted to proceed with an announced probe into federal record-keeping practices if the Benghazi committee does not ultimately recommend action against Kennedy.

Rep. Jason Chaffetz, who chairs the Oversight Committee, was reportedly told by congressional leadership to back off such a probe earlier this year.

"I think there's validity to that investigation. I think it's imperative that they conduct that investigation," Bossie said.

Mark Toner, a State Department spokesman, told reporters on Feb. 10 that Kennedy was unaware of Clinton's server arrangement.

"He did not have knowledge of the computer server that she had set up, the personal email or computer server," Toner said.

He dismissed suggestions that Kennedy had admitted, in his testimony before the Benghazi committee, to prior knowledge of the server in Clinton's home.

"Normally I wouldn't address or read out what was a private interview between Under Secretary Kennedy and members of the Benghazi committee, but on your specific claim that he knew about Secretary Clinton's private server, that's not correct," Toner said in response to a reporter's question.

"And that was made clear in his comments to the Benghazi committee," Toner added. "What he said he was aware of is that she was interested in setting up a private computer in the department so that she could email back and forth with her family during the work day. And as we've said previously, no such computer was ever set up."

Kennedy appears to have been copied on a 2011 email, obtained by the Daily Caller through a Freedom of Information Act lawsuit, that discusses Clinton's "personal server."

But it is unclear what exactly Kennedy knew about Clinton's email arrangement while the two served together at the State Department.

Kennedy reportedly signed off on plans for the temporary diplomatic facility in Benghazi where the 2012 terror attack occurred. He is presently involved in the production of Benghazi-related documents to Congress, a process that has dragged on for more than a year and slowed the select committee's investigation.

"He's still there managing it all," Bossie said of Kennedy. "I would think that there would be enormous interest in what he's doing."