Steve Linick, the State Department inspector general who was fired Friday, is thought to have been investigating whether Secretary of State Mike Pompeo made a staffer run personal errands, according to multiple reports.
Two congressional officials told NBC News on Sunday that they were working to determine whether Linick was conducting additional investigations into Pompeo's conduct. A Democratic aide told CNN that Pompeo was suspected of making a staffer run personal errands such as walking his dog and picking up his dry cleaning.
Representatives for the State Department did not immediately respond to a request for comment from Business Insider.
In a letter to House Speaker Nancy Pelosi on Friday announcing the firing, President Donald Trump said he "no longer" had full confidence in Linick.
"As is the case with regard to other positions where I, as President, have the power of appointment, by and with the advice and consent of the Senate, it is vital that I have the fullest confidence in the appointees serving as Inspectors General. That is no longer the case with regard to this Inspector General," Trump wrote in the letter, according to NBC News.
Inspector generals are meant to conduct independent oversight of government agencies. Linick was the fourth inspector general removed by Trump since April, with the other three having been assigned to the Defense Department, the Department of Health and Human Services, and the intelligence community.
Pelosi said in a statement on Friday night that Linick's firing had "accelerated" what she described as Trump's "dangerous pattern of retaliation against the patriotic public servants charged with conducting oversight on behalf of the American people."
"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," she said.
Rep. Eliot Engel of New York, the chairman of the House Foreign Affairs Committee, and Sen. Bob Menendez of New Jersey, a ranking member of the Senate Foreign Relations Committee, sent a joint letter to the White House on Saturday demanding it forward all records related to Linick's ousting to Congress by May 22.
"President Trump's unprecedented removal of Inspector General Linick is only his latest sacking of an inspector general, our government's key independent watchdogs, from a federal agency," the letter said.
In a statement Friday evening, Engel said he believed Linick's firing was 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," Engel said. "This president believes he is above the law."