The US Department of Justice (DoJ) is being urged to investigate the former MI6 officer behind a controversial dossier about President Donald Trump's alleged links with Russia.
Christopher Steele has been referred to the DoJ by two senior Republican senators over statements about "the distribution of claims contained in the dossier."
Senate judiciary committee chairman Chuck Grassley and Lindsey Graham said they had passed a classified memorandum to the DoJ relating to communications between Mr Steele and "multiple US news outlets".
The emergence of the dossier - containing a series of lurid claims that the Russians had gathered compromising material on the president prior to his election campaign - caused outrage in the Trump camp.
Mr Steele, who runs the London-based Orbis Business Intelligence, was temporarily forced into hiding when he was identified as the author.
Mr Grassley said the decision to refer the case for criminal investigation had not been taken lightly, but he felt obliged to pass on the information unearthed by the committee in the course of its investigations for "appropriate review".
"Maybe there is some innocent explanation for the inconsistencies we have seen, but it seems unlikely. In any event, it's up to the Justice Department to figure that out," he said.
Mr Graham added: "After reviewing how Mr Steele conducted himself in distributing information contained in the dossier and how many stop signs the DoJ ignored in its use of the dossier, I believe that a special counsel needs to review this matter.
"The rule of law depends on the government and all who work on its behalf playing by the rules themselves. I hope the Department of Justice will carefully review our letter and take appropriate action."
In a joint statement, the two senators said the referral did not relate to the veracity of claims contained in the dossier. They added that the referral was for "further investigation only" and was not intended to be an allegation of a crime.
The dossier was reportedly the result of an investigation initially funded by Republicans who were seeking to block Mr Trump from becoming the party's presidential candidate, before being taken over by Democrats after his nomination.
Mr Steele was said to have passed on his findings to both US and UK intelligence in the run-up to the 2016 presidential election due to concerns about national security for both countries.
RPC, the UK law firm representing Mr Steele, declined to comment.
There was no answer at the offices of Orbis Business Intelligence in Grosvenor Gardens in the south-west of the capital on Friday evening.