The White House fired the State Department Inspector General late Friday, according to a State Department spokesperson and a senior congressional aide -- the latest senior U.S. official involved in the impeachment probe into President Donald Trump to be forced out by his administration.
The inspector general, who acts as an independent watchdog responsible for investigating the agency, was investigating Secretary of State Mike Pompeo, according to the chair of the House Foreign Affairs Committee, Rep. Eliot Engel, D-NY.
Pompeo recommended to Trump that inspector general Steve Linick be fired and supported the president's decision, a senior State Department official told ABC News.
MORE: State Dept inspector general's 'urgent' Ukraine briefing underway on Capitol Hill"The President's late-night, weekend firing of the State Department Inspector General has accelerated his dangerous pattern of retaliation against the patriotic public servants charged with conducting oversight on behalf of the American people," Speaker Nancy Pelosi said in a statement released Friday evening. "Inspector General Linick was punished for honorably performing his duty to protect the Constitution and our national security, as required by the law and by his oath."
Under Linick, the inspector general's office had repeatedly found fault with the Trump administration's handling of the agency, especially the treatment of career staff and its efforts to remodel its workforce, including through a damaging hiring freeze.
Appointed to the role in 2013 by President Barack Obama, Linick is a career government lawyer who served as a senior Justice Department official under President George W. Bush and assistant U.S. attorney in California and Virginia under President Bill Clinton.
He is the latest official involved in the House probe to be fired after Trump's effort to withhold military aid and a White House meeting in exchange for a Ukrainian investigation into former Vice President Joe Biden resulted in his impeachment.
But Engel seemed to suggest another reason Linick was ousted, saying late Friday that Linick's office "had opened an investigation into Secretary Pompeo" and that his firing "amid such a probe strongly suggests that this is an unlawful act of retaliation."
"This firing is the outrageous act of a President trying to protect one of his most loyal supporters, the Secretary of State, from accountability," added Engel, accusing Trump of "systematically remov[ing] the official independent watchdogs from the Executive Branch."
In addition to Linick, Trump removed the intelligence community inspector general Michael Atkinson on April 3, who alerted Congress to the whistleblower complaint that ultimately led to his impeachment -- an oversight function required of Atkinson by law. The White House said Trump no longer had confidence in him, while the president said he was "not a big Trump fan, that I can tell you."
MORE: Pelosi, Democrats decry Trump's 'shameful' firing of inspector general amid coronavirus outbreakLinick played a more minor role in the impeachment probe. As ABC News was first to report in October, he requested an urgent meeting with senior lawmakers during the probe to turn over documents his office obtained. Those papers, later confirmed to come largely from Trump's personal lawyer Rudy Giuliani, showed what one senior State Department official called a disinformation campaign that smeared U.S. ambassador to Ukraine Marie Yovanovitch, which appeared to have led to her firing. They also included false claims about Biden, his son Hunter, and the Ukrainian energy company Burisma, whose board Hunter sat on.
Giuliani had turned the documents, based on his interviews with a fired Ukrainian prosecutor accused of corruption, over to Pompeo, who passed them down and said the department would investigate.
Trump has also fired or demoted other top U.S. officials involved in the probe, including his Ambassador to the European Union Gordon Sondland and Lt. Col. Alexander Vindman, both of whom testified, as well as Vindman's twin brother Lt. Col. Yevgeny Vindman, who also served on the National Security Council.
In addition to Linick and Atkinson, Trump has waged something of a war on inspectors general in recent weeks. He effectively removed Glenn Fine, the acting Department of Defense inspector general, who was set to monitor spending from the $2 trillion coronavirus stimulus package. After acting Department of Health and Human Services inspector general Christi Grimm's office released a report on shortages in testing and personal protective equipment amid the coronavirus pandemic, Trump moved to replace her by nominating a full-time candidate, after leaving the post vacant for months.
MORE: Trump abruptly removes inspector general named to oversee $2T in stimulus spendingUnder Linick, the State Department Inspector General's office has repeatedly criticized the agency and its Trump leadership for poor performance. Last November, it found that senior Trump appointees improperly retaliated against a career civil servant over her perceived nationality and political beliefs.
Last August, it said senior political appointees in charge of one bureaus treated employees in a "harsh and aggressive manner" and created a "negative and 'vindictive' environment."
Linick will be replaced by Stephen Akard, who has been the State Department's Director of Foreign Missions since September 2019.
A former senior foreign policy adviser to then-governor Mike Pence, among others, Akard has served at the department since the beginning of the Trump administration as a political appointee.
He was originally nominated to be director general of the Foreign Service -- a role reserved for senior Foreign Service officers, angering many career U.S. diplomats. While Akard served as a Foreign Service Officer from 1997 to 2005 and met the legal requirement, his nomination was eventually withdrawn amid congressional opposition and submitted instead to lead the Office of Foreign Missions.
ABC News' William Mansell contributed to this report.