A former investigator for the House select committee on Benghazi says he was unlawfully fired in part because he sought to conduct a comprehensive probe into the deadly attacks on the US compound, instead of focusing on Hillary Clinton and the State Department.

Air force reserve Major Bradley F Podliska discussed his allegations with the New York Times and CNN. The newspaper on Saturday posted a story based on a draft of a legal complaint Podliska said he plans to file in federal court.

CNN released a story about Podliska ahead of an interview airing on Sunday on its morning programme State of the Union. It also had a draft of the complaint.

Podliska, who described himself as a Republican planning to vote for the GOP nominee for president, said the House committee was engaged in a partisan investigation of the Benghazi attack.

Four Americans, including the ambassador to Libya, were killed when the diplomatic mission came under fire on 11 September 2012.

Podliska said the committee turned all of its attention to Clinton and the State Department after it was revealed that she used a private email server while serving as secretary of state. The move de-emphasized other agencies involved with the attacks and their aftermath, according to a draft of the complaint.

Clinton, the frontrunner for the Democratic nomination for president in 2016, and her supporters have accused House Republicans of trying to use the Benghazi committee to hobble her campaign. She recently called it “nothing but a partisan exercise”.

House majority leader Kevin McCarthy recently linked the committee’s work to Clinton’s sliding poll numbers, drawing a rebuke from Republicans and Democrats.

The California representative stepped back from those remarks, but they damaged his effort to become the next House speaker and this week he dropped out of the race to succeed the outgoing speaker, John Boehner.

In a statement, the committee denied Podliska’s accusations and said it “will not be blackmailed into a monetary settlement for a false allegation made by a properly terminated former employee”.

The committee also said Podliska had shown bias in his investigative work.

Podliska was fired after 10 months on the committee. He disputed what he said were the reasons given for his termination: using work email to send a social invitation to colleagues, assigning an “unauthorized project” to an intern and allegedly putting classified information on an unclassified system.

He contended that another reason he was fired was for taking leave because of a deployment. Such a dismissal would be illegal.