WASHINGTON — President Trump’s congressional allies trained their fire on the special counsel investigation on Tuesday, armed anew with a damaging report showing that the lead F.B.I. agent assigned to the case held strong anti-Trump views when the inquiry began.

Mr. Trump’s loyalists in the House and other Republicans used the report, released last week by the Justice Department’s inspector general, to cast the F.B.I. as part of an out-of-touch Washington bureaucracy that disdained both Mr. Trump and the blue-collar voters who swept him into office. And they argued that the 500-page document showed that top officials let the blindfold of justice slip so that personal politics influenced their work.

Though the report focused on the investigation into Hillary Clinton’s use of a private email server and found no evidence that political bias influenced the outcome of that case, Republicans could hardly have asked for a better weapon for assailing the special counsel, Robert S. Mueller III. And for the second day of hearings on Capitol Hill with the inspector general, Michael E. Horowitz, they showed they intended to use it.

The attacks most likely foreshadowed a Republican strategy for the rest of the Mueller investigation, which is studying whether Mr. Trump tried to obstruct justice and whether anyone in his campaign conspired with Russian operatives to influence the 2016 presidential election. Mr. Trump has already claimed the report exonerated him and on Tuesday, his campaign manager, Brad Parscale, said the report gave Mr. Trump justification to fire his attorney general and end the Mueller investigation.

At the heart of Republicans’ criticism were two senior F.B.I. officials, Peter Strzok and Lisa Page, who exchanged text messages about their dislike of Mr. Trump, his supporters and his policies — even as they investigated his campaign’s ties to Russia.

“Just went to a southern Virginia Walmart,” Mr. Strzok wrote in August 2016, just a few weeks into the Russia investigation. “I could SMELL the Trump support.”

Representative Jim Jordan, Republican of Ohio, said such quotes have undermined public faith in the F.B.I. in ways that stretch beyond the Clinton investigation. “The arrogance and condescension and the elitist attitude, that’s what ticks people off,” he said. “As they look at all this and see what Strzok said throughout these investigations, that’s why their confidence is so shaken.”

Democrats appeared frustrated at times as they accused Republicans of using the report to try to discredit Mr. Mueller. “The report has nothing to say about the ongoing work of the special counsel,” said Representative Jerrold Nadler of New York, who holds the top Democratic slot on the Judiciary Committee. “Their argument is based on innuendo, and not on the facts, and certainly not on this report.”

Mr. Nadler and others noted that the F.B.I.’s actions during the presidential election almost uniformly harmed Mrs. Clinton’s candidacy. The former F.B.I. director, James B. Comey, was unusually frank and public in his remarks about Mrs. Clinton, even as he hewed closely to the rules and did not reveal that his agents were also investigating the Trump campaign.

Mr. Horowitz’s report found no evidence that political bias influenced key investigative decision-making, but he offered Democrats no relief from criticism that the text messages had raised questions about the credibility of the investigation.

“They weren’t just speaking about a generic election that they cared about,” Mr. Horowitz said. “It just so happened that the people they were speaking about had a connection to the investigations they themselves were working on.”

Mr. Strzok has said he is willing to testify about his text messages and his role in the investigation. No date has been set. Mr. Strzok was removed from the special counsel’s investigation when the text messages were discovered. He was reassigned to the human resources department, and his lawyer confirmed on Tuesday that he was escorted from F.B.I. headquarters as part of “ongoing internal proceedings.” He still works for the bureau, according to the lawyer, Aitan Goelman. Ms. Page has left the F.B.I.

While Democrats say the inspector general’s report closed the book on the question of Mrs. Clinton’s investigation, Mr. Trump and his allies are looking to the future. They argue that Mr. Mueller’s inquiry was born out of investigative bias.

“The F.B.I. is oath-bound to remain neutral and enforce the law impartially and fairly,” said Representative Scott DesJarlais, Republican of Tennessee. “How can we accomplish this when there are agents that are actively biased against our sitting president?”