Congressional and FBI investigators are homing in on the Trump-Russia dossier

A collection of explosive memos alleging ties between President Donald Trump’s campaign team and Russia is being examined by both the Senate Select Committee on Intelligence and special counsel Robert Mueller as part of their separate but parallel probes into Russia’s election interference.

The Senate Intelligence Committee’s vice chairman, Democratic Sen. Mark Warner, told reporters Wednesday that the committee has been working “backwards” to try to verify the memos, which were published in full by BuzzFeed in January.

The nation’s top intelligence officials at the time briefed both President Barack Obama and the then-President elect Trump on the dossier’s allegations, many of which appear to align with events during the campaign and are slowly being corroborated.

Reuters reported Wednesday that Mueller has “taken over” inquiries into the dossier that were started by the FBI when Director James Comey was still leading the bureau.

The FBI had been using the dossier as a “roadmap” for its investigation into Trump’s ties to Russia, the BBC reported in March. CNN reported later that the FBI had used the dossier’s raw intelligence to strengthen its case for a warrant that would allow them to surveil early Trump campaign adviser Carter Page.

The FBI may have been taking cues from Steele’s dossier because it has worked with him in the past.

Steele, who cultivated an extensive network of Russian sources during his decades on MI6’s Moscow desk, worked with the FBI on Russia- and Ukraine-related matters between 2013 and 2016 – specifically with the FBI’s Eurasian Joint Organized Crime Squad, according to Vanity Fair.

The squad “was a particularly gung-ho team with whom Steele had done some heady things in the past,” Vanity Fair reported. “And in the course of their successful collaboration, the hard-driving FBI agents and the former frontline spy evolved into a chummy mutual-admiration society.”

The relationship was so “chummy” that the FBI offered to pay Steele to continue his work in October, The Washington Post reported in March. By that point, supporters of Democratic nominee Hillary Clinton had taken over the funding for Steele’s work from anti-Trump Republicans.

Steele was ultimately never paid by the FBI. His last memo was dated December 13, 2016.

The dossier includes details about an alleged quid-pro-quo in which Russia agreed to leak the hacked Democratic National Committee emails to WikiLeaks in exchange for the Trump campaign sidelining Russian aggression in Ukraine as a campaign issue. It also alleges that Trump’s former campaign chairman, Paul Manafort, managed the communication between Russia and the campaign.

While he was campaign chairman, Manafort offered to give “private briefings” about the Trump campaign to a Russian oligarch and ally of Russian President Vladimir Putin, according to emails reviewed last month by The Washington Post and The Atlantic. Manafort also asked a longtime Russian-Ukrainian employee in early April how he could use his media coverage and high-level campaign role to collect past debts.

Some of the dossier’s more outlandish claims, including salacious accounts of sexual escapades, have not been corroborated. Details in the dossier about Trump’s personal lawyer, Michael Cohen, also appear to be inaccurate. Trump has dismissed the dossier as “phony stuff” and “fake news.”

The Senate Intelligence Committee has been “incredibly enlightened” so far at its “ability to work backwards” from the dossier from June-November 2016, said Sen. Richard Burr, its Republican chairman. But “getting past that point has been somewhat impossible” without testimony from Steele, who has so far declined to appear before the committee.

It is unclear whether the committee has been using the dossier as a roadmap for its investigation, or if it’s attempting to verify its claims as a part of the wider probe into possible collusion.

Representatives for Burr and Warner declined to comment.