But both the circumstances of its release and the vivid picture it paints of Simpson’s operation and his chief Russia investigator, Christopher Steele, provided fresh ammunition to both sides of a growing fight over the dossier.

In his testimony, Simpson sought to portray himself as an astute researcher well versed in the Russian government and that country’s organized crime. And he said Steele, the former British spy he hired to investigate the campaign’s ties to Russia, had “a Sterling reputation as a person who doesn’t exaggerate, doesn’t make things up, doesn’t sell baloney.”

Steele believed that his investigation had unearthed “a security issue about whether a presidential candidate was being blackmailed,” Simpson told the committee.

Simpson and Peter Fritsch, the firm’s co-founders, had called for the Judiciary Committee to release the transcript in an op-ed essay in The New York Times, arguing that it would show that Republicans were unfairly smearing their work. The request inspired a tart back-and-forth with Sen. Charles E. Grassley of Iowa, the committee’s Republican chairman, but appeared to be going nowhere until Tuesday, when Feinstein took the side of Fusion.

“The American people deserve the opportunity to see what he said and judge for themselves,” she said. “The innuendo and misinformation circulating about the transcript are part of a deeply troubling effort to undermine the investigation into potential collusion and obstruction of justice. The only way to set the record straight is to make the transcript public.”

For Feinstein and Grassley, two senior senators who worked closely last summer to initiate a joint Russia investigation, the breach was striking. But it reflects the growing divide between the two parties.

Republicans have repeatedly and vocally raised concerns that the dossier — a set of reports paid for by Democrats — could have been mishandled by the FBI as it was opening its own investigation into the Russian effort and the Trump campaign. Democrats say scrutiny of the dossier’s provenance is a distraction from the central question: Did the Trump campaign knowingly seek aid from Russia?

Democrats were still seething Tuesday at the decision by Grassley and another Republican on the panel, Sen. Lindsey Graham of South Carolina, to issue a criminal referral last week for Steele. The senators said they had reason to believe Steele had lied to federal authorities about his contacts with the media and urged the Justice Department to investigate.

A spokesman for Grassley said Feinstein’s decision was “totally confounding.”

“Her action undermines the integrity of the committee’s oversight work and jeopardizes its ability to secure candid voluntary testimony,” the spokesman, Taylor Foy, said.

Simpson said that he hired Steele in the late spring of 2016 and that the former spy grew alarmed soon after getting to work. With Simpson’s blessing, he reached out to an old contact at the FBI in early July.

“To me, it was like, you know, you’re driving to work and you see something happen, and you call 911,” Simpson said.

Current and former U.S. and foreign officials with direct knowledge of the investigation say that the federal inquiry did not start with Steele’s dossier, early parts of which did not reach counterintelligence investigators at the FBI until August, after the bureau’s inquiry had already begun. But the officials have said that the dossier added material and buttressed what U.S. law enforcement and spy agencies were gleaning from other sources.

According to Simpson, it was not until late September, nearly two months after the FBI investigation had begun, that the FBI reached out to Steele. He then met with agents in Rome to brief them on his work.

At that meeting, Steele learned that his information was considered credible by the FBI “because they had other intelligence that indicated the same thing and one of those pieces of intelligence was a human source from inside the Trump organization,” Simpson testified.

Simpson did not disclose the identity of the human source in his August testimony. But people familiar with the matter said that Steele, after being questioned by the FBI, came to believe that the bureau’s human source was George Papadopoulos, a former Trump campaign foreign adviser.

In fact, the source was an Australian diplomat who had spent a night drinking in London with Papadopoulos in the spring and then shared with U.S. officials what he had learned from the Trump aide.

Simpson said Fusion played no role in deciding what to include in the memos that would eventually be compiled into the dossier.

But Simpson said that Steele “broke off” his connections with the FBI after The New York Times ran an article Oct. 31 that said the bureau had found no conclusive or direct link between Trump and the Russian government.

Citing law enforcement officials, the Times article said that “none of the investigations so far have found any conclusive or direct link between Mr. Trump and the Russian government.”

Since then, investigators and journalists have developed extensive evidence linking Trump’s associates to Russian government and intelligence operatives, but as yet there is still no public evidence of a direct link between Trump himself and the Kremlin.

At the time, many in the FBI did not believe Russia was aiming to explicitly help Trump. That consensus did not emerge fully until January 2017 when U.S. intelligence agencies released a report saying that the Kremlin’s intentions were twofold: to “undermine public faith in the U.S. democratic process” and to “help President-elect Trump’s election chances.”

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Simpson, in his testimony, called the Times article “a real Halloween special.”

“There was a concern that the FBI was being manipulated for political ends by the Trump people and that we didn’t really understand what was going on,” Simpson said. “So he stopped dealing with them.”

The concerns prompted Steele to share his work with a former British diplomat, who passed the information to Sen. John McCain after the election.

McCain is believed to have then met with James B. Comey, then the FBI director, to discuss the dossier. In January, weeks before the inauguration, the dossier became public after news broke that Comey had briefed President Barack Obama and Trump on Steele’s work.

The release of the transcript broke what had more or less been a prevailing rule of secrecy around Congress’s various investigations into Russia’s efforts and the Trump campaign. Although pieces of information from witness interviews in the House and the Senate have leaked to the news media, only two complete transcripts — from House Intelligence Committee interviews with Carter Page and Erik Prince — had been publicly released among hundreds.

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In a brief interview, Feinstein left open the possibility of releasing other transcripts from the committee’s investigation.

The New York Times