The Washington research firm has been under attack by the White House and Republican lawmakers over the dossier, which is central to investigations in Congress and by a federal special counsel into allegations that Russian Federation interfered in the election to help Trump win, and any potential collusion by the Trump campaign.
Tuesday's transcript release by Feinstein, the Democratic ranking member on the Senate Judiciary Committee, comes after senior Democrats on the panel had urged its chairman, Senator Chuck Grassley, to release it. "The only way to set the record straight is to make the transcript public".
In a 312-page transcript of Simpson's August 2017 interview with the Senate Judiciary Committee, Simpson's attorney also said it was risky to discuss the dossier's sources because its public release previous year had already led to murder.
The resulting memos, written over the summer and fall of 2016, were explosive: They alleged that the Russian government had compromising material on the president and that Trump's campaign colluded with Russia to defeat Clinton during the presidential elections.
In their letter, Whitehouse and Blumenthal echoed complaints by Fusion GPS that Simpson's testimony has been selectively leaked, and they rejected the idea the company's work was the basis for the start of the investigation into Russia's interference with the 2016 election.
Russian Federation has repeatedly denied allegations of meddling in the USA election and Trump denies any collusion between his campaign and Moscow officials. He said that he would like Fusion partners to appear for public testimony. "The transcript of Glenn Simpson's lengthy responses to the Senate Judiciary Committee's questioning speaks for itself".
Instead, the person said Tuesday, the episode Simpson was apparently referring to involved communication between George Papadopoulos, a foreign policy adviser for the Trump campaign who has since pleaded guilty to lying to the Federal Bureau of Investigation, and an Australian diplomat.
"My understanding was that they believed Chris at this point - that they believed Chris's (Steele's) information might be credible 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 said.
"The American people deserve the facts", Sen.
Grassley spokesman Taylor Foy said that Feinstein released the transcript without consulting Grassley and suggested it could jeopardize the committee's ability to interview future witnesses.
Senate Dianne Feinstein on Tuesday released the 312-page transcript of Simpson's appearance, saying she needed to combat "innuendo and misinformation" being spread about the interview. In a statement, Fusion GPS commended Feinstein "for her courage" in releasing the document.
Last week, Grassley and fellow Republican Sen.