Two U.S. senators have called for a criminal investigation of a former British spy who authored a salacious report about Donald Trump when he was a businessman, a report known as the Steele Dossier.

The letter, released on Friday by Republicans Chuck Grassley and Lindsey Graham, adds to the turmoil that has plagued the Trump administration and will likely deepen the bipartisan rancor in Congress over both the dossier and also interactions between Trump associates and Russian officials. 

In their letter, the two called on the Justice Department to investigate Christopher Steele for what they alleged were false statements Steele made about how the dossier was circulated. 

“This referral does not pertain to the veracity of claims contained in the dossier,” the senators said in a statement.

Steele and his lawyers could not immediately be reached for comment. 

Former British spy

Steele, a former MI6 officer with deep experience in Russia, was hired by a Washington-based political research firm known as Fusion GPS in the summer 2016. 

Fusion had earlier been retained by a Republican donor interested in gathering embarrassing political dirt on Trump, but after Trump won the Republican nomination, Fusion was hired by a law firm with connections to the Democratic Party. 

Steele’s research, which focused on Russia and Trump’s ties there, resulted in a 35-page report that circulated among political operatives and reporters in Washington for months until BuzzFeed published the entire dossier online in January 2017. 

News reports have said the FBI had considered paying Steele for more research but later decided not to. 

Trump has repeatedly denied the allegations in the dossier. Some Republicans have also asserted that the dossier was what prompted the FBI to open its criminal investigation in July 2016 into Russia’s interactions with Trump-connected officials, something contradicted by court documents and other public statements. 

Grassley calls for inquiry

Grassley, who heads the Senate Judiciary Committee, earlier called for a Justice Department investigation of Fusion GPS, suggesting the firm was involved in a Russian-linked lobbying campaign to undermine the 2012 U.S. Magnitsky Act, which punishes Russians deemed to be human rights abusers. 

In an opinion piece published in The New York Times on Tuesday, the founders of Fusion GPS accused Republican lawmakers of trying to obscure Trump’s Russian connections and called on Grassley to release transcripts of their testimony to the Judiciary Committee. 

The Judiciary Committee is one of three congressional panels investigating interactions between Trump associates and Russian officials. 

The FBI probe, now taken over by special counsel Robert Mueller, has resulted in two indictments and two guilty pleas, including from Trump’s first national security adviser, Michael Flynn.