Congressman Adam Schiff is facing renewed criticism and denunciations for his role in amplifying the false claims that President Trump colluded with the Russian Federation during the 2016 election, even as the Durham report lays blame for the investigatory abuse squarely at the feet of the FBI. Mr. Schiff, a zealous progenitor of the Trump-Russia investigations, is now facing calls for his expulsion from the House.

On Monday, Special Counsel John Durham ended a years-long investigation into the origins of the Russian collusion investigation, the practices of those agents who looked into those claims, and the investigation’s ramifications. In his report, Mr. Durham says that the FBI acted improperly. 

“Again, the FBI’s failure to critically analyze information that ran counter to the narrative of a Trump/Russia collusive relationship exhibited throughout Crossfire Hurricane is extremely troublesome,” the report said. The FBI had given the investigation the “Crossfire Hurricane” code name. 

The Durham report has led to fresh attacks on Mr. Schiff, whose committee eagerly pursued Mr. Trump during the Russian investigations. Mr. Schiff has been accused over the last few years of making numerous falsehoods and misrepresentations during the Democrat-controlled Trump congressional investigations, of which Mr. Schiff was a leader.

In one notable section of his report, Mr. Durham found that one researcher with ties to a government agency felt “threatened” when meeting with Mr. Schiff’s staff about cybersecurity matters in the days after the 2018 midterm elections, when Mr. Schiff was poised to take over the Intelligence Committee. 

During this meeting, the researcher said Mr. Schiff’s staff presented him with a news article claiming there was a back channel between the Trump campaign and Russia’s Alfa Bank. Mr. Schiff’s staff asked that the researcher help get to the bottom of the allegations. 

The researcher, though, felt it would be inappropriate to do so, as he was an employee of a public university. The Democratic staffers then allegedly told the researcher that “they were now in charge,” which he “took … as a mild threat.”

Mr. Schiff decried the “flawed” Durham report to MSNBC’s Lawrence O’Donnell on Tuesday. “This was an investigation that started in a flawed manner, it was conducted in a flawed manner, and its conclusion is a flawed conclusion,” he said. 

One of Mr. Schiff’s colleagues, Congresswoman Anna Paulina Luna, introduced a resolution on Wednesday to expel Mr. Schiff from Congress. “Knowingly using your position on House Intel to push a lie that ripped apart our country, cost taxpayers millions of dollars, and authorized spying on a US President and then proceeding to double down on the lie within days of the Durham report coming out makes you unfit for office,” Ms. Luna wrote on Twitter. 

Ms. Luna continued, saying that Mr. Schiff brought “dishonor to the House of Representatives.”

A former House Intelligence Committee chairman, Mr. Schiff was barred from serving on that committee after claims about Russian collusion in the 2016 election were debunked. Speaker McCarthy said Mr. Schiff “severely undermined” the committee’s “primary national security and oversight missions.” 

In response, Mr. Schiff said Mr. McCarthy “will soon find out just how wrong he is” in assuming Mr. Schiff will go quietly. A few days later, Mr. Schiff entered the race to succeed Senator Feinstein, and sent fundraising emails claiming to be a victim of Republican wrath. 

While serving as the acting United States attorney in Connecticut, Mr. Durham was appointed in 2019 by Mr. Trump’s attorney general, Bill Barr, to investigate the origins of the FBI and Department of Justice’s Russia collusion probe. 

Mr. Durham took control of this investigation shortly after another special counsel, Robert Mueller, completed his investigation into whether the 2016 Trump campaign had colluded with Russia to move the outcome of the election in his favor.

The Mueller investigation resulted in roughly three-dozen criminal charges, including convictions of a half-dozen Trump associates, and concluded that Russia intervened on the Trump campaign’s behalf and that the campaign welcomed the help. 

Mr. Mueller’s team did not find that they actually conspired to sway the election, creating an opening for critics of the probe — including Mr. Barr himself — to complain that it had been launched without a proper basis.

The Russia investigation began during the 2016 presidential election after the FBI learned from an Australian diplomat that a low-level campaign aide for Mr. Trump, George Papadopoulos, drunkenly claimed to know of “dirt” that the Russians had on Secretary Clinton.