© McCain Institute
Senator John McCain • David Kramer
Sen. John McCain associate David Kramer, who passed along the Trump dossier to McCain, who in turn gave it to the FBI, reportedly pleaded his Fifth Amendment right against self-incrimination rather than testify before the House Intelligence Committee.

Fox News reported that Kramer, a State Department official under President George W. Bush, traveled to England in mid-November 2016, following then-President Elect Donald Trump's upset win over Hillary Clinton, to meet with dossier author Christopher Steele.

Kramer, who currently leads the McCain Institute, ultimately received a physical copy of the document from Fusion GPS co-founder Glen Simpson back in the United States and then gave it to McCain, according to The Washington Post.

Fusion GPS is the opposition research firm paid by the Clinton campaign and the Democratic National Committee to produce the dossier.

McCain denied passing the document filled with unverified information along to the media, claiming he had only shared it with one other person. "I gave it to no one except for the director of the FBI," the senator said in what The Daily Caller described as a testy exchange last October. "I don't know why you're digging this up now."

In a statement released in January 2017, McCain said: "Late last year, I received sensitive information that has since been made public. Upon examination of the contents, and unable to make a judgment about their accuracy, I delivered the information to the Director of the FBI. That has been the extent of my contact with the FBI or any other government agency regarding this issue," he added.

Kramer's unwillingness to testify may represent a desire to refrain from implicating not only himself, but also McCain in trafficking the partisan dossier, which was used by the Obama administration to obtain surveillance warrants on Trump campaign figures.

Breitbart's Aaron Klein noted the fact that Kramer had acted as the liaison between Simpson and McCain "marked the clearest indication yet that McCain may have known that the dossier originated with Fusion GPS, meaning that he may have knowingly passed on political material to the FBI."

"Until now, it has not been clear whether McCain was aware of the origins of the dossier when he hand delivered the unsubstantiated document to (then FBI Director James) Comey," Klein wrote. "It is still not clear whether McCain knew that Fusion GPS's anti-Trump work resulting in the dossier was funded by Hillary Clinton's 2016 presidential campaign and the Democratic National Committee (DNC) via the Perkins Coie law firm," he added.

Shortly before the president-elect's inauguration in 2017, Comey briefed Trump on the existence of the dossier. The document was later leaked to the public, leading to a media frenzy about Trump and alleged Russia collusion. Arguably, that narrative helped justify the appointment of special counsel Robert Mueller to conduct the Russia investigation in May 2017.

Trump has repeatedly stated that there was no collusion between his campaign and Russia, and Mueller's team has yet to file an indictment alleging such.

The president has stated the real focus of the investigation should be on the Obama administration and the former secretary of state's presidential campaign.