A Republican staffer from the House Select Committee on Benghazi has been fired after he says he developed concerns about the politicized nature of the panel’s investigation.

The criticism from an experienced Republican intelligence investigator comes amid growing Democratic Party complaints that the special committee was on a mission to undermine former secretary of state Hillary Rodham Clinton and her bid for the presidency.

A spokesman for the committee denied the allegations from the former staffer, Bradley Podliska, a major in the Air Force Reserve who issued a statement through his attorneys Saturday afternoon.

“My non-partisan investigative work conflicted with the interests of the Republican leadership, who focused their investigation primarily on Secretary Clinton and her aides,” Podliska said, especially after reports surfaced in March that Clinton has used a private e-mail server. “The families of the Americans who died in the Benghazi attacks deserve to find out the truth about Benghazi, but to do that a thorough, non-partisan investigation must be conducted of all agencies and officials involved in Benghazi,” the statement said.

In a news release Saturday, the committee called Podliska’s claims “transparently false,” stating that he “was terminated for cause.” The written statement, attributed to a committee spokesman, did not mention Podliska by name but said the former employee had shown poor judgment.

“The employee actually was terminated, in part, because he himself manifested improper partiality and animus in his investigative work’’ against the Obama administration, including Clinton, the statement said.

The new developments come at a difficult time for committee Republicans, who plan to question Clinton on Oct. 22 despite growing requests to shut down the inquiry.

The ranking Democrat on the Benghazi panel, Rep. Elijah E. Cummings (Md.), said Saturday evening that Podliska’s allegations provide more proof of serious bias by the committee’s majority.

“Republicans have been abusing millions of taxpayer dollars for the illegitimate purpose of damaging Hillary Clinton’s bid for president,” Cummings said, pointing out that the latest complaints come from “one of Chairman [Trey] Gowdy’s own handpicked investigators.”

The ranking Democrat on the House Intelligence Committee, Rep. Adam B. Schiff (Calif.), called for an end to the committee on Saturday.

“Only by ending this expensive and politicized investigation can we begin to undo the damage already done through this unprecedented use of Congress’s power for nakedly political purposes.”

Gowdy (R-S.C.) has defended the panel’s work, insisting that he has found important new documents to be released this week involving e-mails from Clinton’s longtime adviser, Sidney Blumenthal, who offered intelligence advice on Libya.

Podliska’s attorneys, Peter Romer-Friedman and Joe Napiltonia, said they expect to file a lawsuit for wrongful termination soon that will make the case that Podliska was fired in part because he participated in required National Guard exercises. Napiltonia said his client was terminated after notifying the committee of his active-duty military obligations. Retaliation for an employee taking military leave would violate federal law protecting the rights of uniformed military personnel, the lawyers said.

They say that Republican committee staff members questioned Podliska’s military obligations along with their client’s preference for a nonpartisan inquiry into the events in Libya.

Podliska, currently stationed in Germany, could not be reached for comment. His criticism was first reported Saturday afternoon by the New York Times.

Brian Fallon, a spokesman for Clinton’s campaign, called the former employee’s claims “explosive allegations” that “may provide the most definitive proof to date that this taxpayer-funded investigation has been a partisan sham from the start.”

In rejecting Podliska’s claims earlier, the committee said Podliska had received “repeated counseling for performance and lack of judgment.” The statement said he had shown an eagerness to push claims against the Obama administration after joining the panel in the fall of 2014.

“One reason for which the employee was terminated was his repeated efforts, of his own volition, to develop and direct Committee resources to a PowerPoint ‘hit piece’ on members of the Obama Administration — including Secretary Clinton,” the committee’s statement said. “Thus, directly contrary to his brand new assertion.”

Further, the statement said that “the former employee has violated this confidentiality requirement in a public way” and that he never previously made claims of bias.

Napiltonia said the committee’s allegations of Podliska’s poor job performance are “completely false.”

“I would note that Mr. Podliska was never reprimanded prior to his giving notice that he was going on military leave in March,” Napiltonia said Saturday after reviewing the committee’s statement. Podliska spent more than a decade as an intelligence analyst with a defense agency. “He is a proud conservative Republican,” said Napiltonia, one who always hoped the committee would investigate all agencies and individuals involved in the Benghazi tragedy.

From the outset, Republican members of the House have rebuffed complaints about bias on the Benghazi panel, insisting that the committee was examining the violence in Libya that led to the death of U.S. Ambassador J. Christopher Stevens and three other Americans on Sept. 11, 2012. Increasingly, Democrats expressed doubt about the committee’s work and the intentions of Gowdy.

The controversy deepened Tuesday when House Majority Leader Kevin McCarthy (R-Calif.) made comments that appeared to reinforce criticism that the committee’s primary target was Clinton. The GOP majority leader, who at the time was a candidate to succeed John A. Boehner (Ohio) as speaker, suggested in a Fox News interview that the committee had succeeded because Clinton’s poll numbers had plummeted.

Anne Gearan contributed to this report.