A Russia analyst who provided information for a dossier of research used during the Trump-Russia investigation has been arrested by U.S. authorities as part of an ongoing special counsel investigation, the Justice Department said Thursday.

Igor Danchenko is the third person, and second in a two-month span, to face charges in special counsel John Durham’s probe into the origins of the Russia investigation.

Danchenko functioned as a source for Christopher Steele, a former British spy who was paid by Democrats to examine ties between Russia and Donald Trump during the 2016 presidential campaign. The research he compiled was provided to the FBI and used by federal authorities as they applied for and received surveillance warrants targeting a former Trump campaign aide aide.

Both the dossier and the Durham probe are politically charged. Trump’s Justice Department appointed Durham as Trump claimed the investigation of campaign ties to Russia was a witch hunt and pointed to the dossier, some of which remains uncorroborated or has been discredited, as evidence of a tainted probe driven by Democrats.

But the dossier had no role in the launching of the Trump-Russia investigation and special counsel Robert Mueller ultimately found questionable ties between the Trump campaign and Russia, but not sufficient evidence to pursue criminal charges. Democrats have lambasted the Durham probe as politically motivated, but the Biden administration has not stopped it.

The Justice Department’s inspector general has faulted the FBI and the Justice Department for their handling of the dossier. Danchenko — who was not identified by name in the watchdog report — had revealed to FBI investigators during a 2017 interview about the dossier’s origins and veracity — “potentially serious problems with Steele’s descriptions of information in his reports.”

But those qualms from Danchenko were omitted from the final three surveillance applications, making the dossier appear more credible than even one of its own sources thought it was, according to the report from Inspector General Michael Horowitz.

Danchenko, who previously worked for the Brookings Institution, has himself suggested that the information he offered to Steele was not meant to be portrayed as indisputable fact.

“Even raw intelligence from credible sources, I take it with a grain of salt,” Danchenko said in an interview with The New York Times last year. “Who knows, what if it’s not particularly accurate? Is it just a rumor or is there more to it?”

It was not immediately clear what charges Danchenko might face. But it would be the third criminal action brought by Durham, following the September indictment of Michael Sussmann, a cybersecurity lawyer accused of making a false statement to the FBI during a 2016 meeting, and a guilty plea last year from an FBI lawyer who admitted altering an email related to the surveillance of the Trump aide, Carter Page.

Justice Department spokesman Wyn Hornbuckle confirmed Danchenko’s arrest, first reported by The New York Times. A lawyer for Danchenko had no immediate comment.