The British spy who compiled a controversial and unverified dossier that alleges Russia possesses compromising information about then-candidate Donald Trump apparently went to the FBI out of fears that Trump "was being blackmailed." The explosive details are just some what have emerged from the newly public transcript of Fusion GPS co-founder Glenn Simpson's testimony before the Senate Judiciary Committee, which was released by ranking Democrat Sen. Dianne Feinstein (D-Calif.) on Tuesday. Fusion GPS is famously behind a controversial dossier compiled by British spy Christopher Steele, who was hired by Simpson.

Simpson told the Senate in his testimony about Steele's fears that Trump was being blackmailed. "[T]he whole problem of compromise of Western businessmen and politicians by the Russians is an essential part of — it's like disinformation, it's something they worry about a lot and deal with a lot and are trained to respond to," Simpson said. "So, you know, a trained intelligence officer can spot disinformation that you or I might not recognize, and certainly that was Chris' skill, and he honed in on this issue of blackmail as being a significant national security issue."

Simpson added that the FBI apparently "believed Chris' 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." A person in Fusion GPS's orbit, though, told NBC that was a mischaracterization of an Australian diplomat's tip that Russia has dirt on Hillary Clinton, as had been shared with him by George Papadopoulous "during a night of heavy drinking at an upscale London bar in May 2016," The New York Times reports. Read the full transcript here. Jeva Lange