Democratic presidential candidate Hillary Clinton delivers remarks at the Congressional Hispanic Caucus Institute’s 38th annual Awards Gala in Washington October 8, 2015.

A former investigator for the House of Representatives Select Committee on Benghazi is accusing the Republican-led panel of targeting Democrat Hillary Clinton to scupper her presidential bid, the New York Times and CNN reported on Saturday.

They said Major Bradley Podliska, an intelligence officer in the Air Force Reserve on active duty in Germany, alleged that he was fired for resisting pressure to focus his investigation into the 2012 attack on the U.S. diplomatic compound in Benghazi on Clinton’s role. They said he planned to file a complaint in federal court next month.

“These are explosive allegations,” Clinton campaign spokesman Brian Fallon said in a statement. “This Republican whistleblower’s account from inside the Benghazi Committee may provide the most definitive proof to date that this taxpayer-funded investigation has been a partisan sham from the start.”

The committee on Saturday strongly denied the media reports.

“Contrary to his brand new assertion, the employee actually was terminated, in part, because he himself manifested improper partiality and animus in his investigative work. The Committee vigorously denies all of his allegations,” a committee spokesperson said in a statement.

The committee has come under criticism since Representative Kevin McCarthy, the No. 2 House Republican who had been expected to become speaker of the House, suggested in a television interview last week that the taxpayer-funded investigation into Benghazi was designed to hurt Clinton as she seeks the Democratic presidential nomination.

McCarthy later said he had not meant to suggest the committee’s purpose had been to harm the former secretary of state’s chance of winning the November 2016 election. On Thursday McCarthy bowed out of the Speaker race, leaving the Republicans in disarray.

Saturday’s reports on Podliska drew sharp reactions from Democrats.

“These are extremely serious whistleblower charges … Republicans have been abusing millions of taxpayer dollars for the illegitimate purpose of damaging Hillary Clinton’s bid for president,” Representative Elijah Cummings, ranking Democrat on the committee, said in a statement.

“Even before Kevin McCarthy’s comments laid bare the true intent of the committee, it’s been clear that Secretary Clinton has been the true target of this investigation. It’s time to shut down the Benghazi Select Committee,” Representative Adam Schiff of California said in a statement.

On Wednesday, Democratic Representative Alan Grayson of Florida filed an ethics complaint against McCarthy and the committee’s chairman, Trey Gowdy, saying that federal funds for the Benghazi committee were being used for political purposes.

CNN quoted Podliska as saying in an interview due to be aired on Sunday that the committee pulled resources away from probes of other individuals and agencies to focus almost exclusively on Clinton and the State Department she helmed for four years.

“I knew that we needed to get to the truth to the victims’ families. And the victims’ families, they deserve the truth — whether or not Hillary Clinton was involved, whether or not other individuals were involved,” CNN quoted Podliska as saying.

Clinton, the top U.S. diplomat at the time of the Benghazi attack in 2012, is due to testify before the committee for the first time Oct. 22.

Her campaign and fellow Democrats have seized on McCarthy’s comments as proof that this was a politically motivated investigation focusing on the candidate rather than the incident, in which U.S. Ambassador Chris Stevens and three other Americans were killed.

The committee is due to release the findings of its investigation next year, as the presidential race heats up.