The extraordinary but unverified documents published on Tuesday on Donald Trump’s ties with Moscow began life as a piece of opposition research, which has become as much a part of US politics as yard signs and coloured balloons.
There is a small industry of research and investigative firms in Washington, typically staffed by a mix of former journalists and security officials, adept at finding information about politicians that the politicians would rather stay hidden.
The firms often do not know who exactly is hiring them; the request could come from a law firm acting on behalf of a client from one of the parties.
In this case, the request for opposition research on Donald Trump came from one of his Republican opponents in the primary campaign.
The research firm then hired one of its sub-contractors who it used regularly on all things Russian: a retired western European former counter-intelligence official, with a long history of dealing with the shadow world of Moscow’s spooks and siloviki (securocrats).
By the time the contractor had started his research, however, the Republican primary was over. The original client had dropped out, but the firm that had hired him had found a new, Democratic client.
This was not necessarily the Hillary Clinton campaign or the Democratic National Committee. Opposition research is frequently financed by wealthy individuals who have donated all they can and are looking for other ways to help.
By July, the counter-intelligence contractor had collected a significant amount of material based on Russian sources who he had grown to trust over the years – not just in Moscow, but also among oligarchs living in the west. He delivered his reports, but the gravity of their contents weighed on him.
If the allegations were real, their implications were overwhelming.
He delivered a set to former colleagues in the FBI, whose counter-intelligence division would be the appropriate body to investigate.
It is believed he also passed a copy to his own country’s intelligence service, but it felt constrained in what action it could take and left it up to the Americans to do their own investigation and draw their own conclusions.
As summer turned to autumn, the investigator was asked for more information by the FBI but heard nothing back about any investigation. The bureau seemed obsessed instead with classified material that flowed through a private email server set up by Clinton’s aides.
The FBI’s director, James Comey, threw the election into a spin 11 days before the vote by announcing his investigators were examining newly discovered material.
The former intelligence official grew concerned that there was a cover-up in progress. On a trip to New York in October, he decided to pass the material to the press. He met David Corn, the Washington editor of Mother Jones, who first reported their existence on 31 October.
The FBI however continued to refuse to comment on the issue, despite reports that it had requested and perhaps acquired a warrant for further investigation from the Foreign intelligence surveillance (Fisa) court. The silence was not altogether surprising.
The FBI counter-intelligence division, headquartered in Washington, is extremely secretive, much more so than the New York field office, which had strong links to former prosecutor and mayor Rudy Giuliani, who was by then working for Trump.
The threat of leaks from New York about Clinton emails had reportedly pushed Comey into making his October surprise announcement.
In mid-November, the documents took another route into Washington that ultimately led to them being mentioned in the joint intelligence report on Russian interference that was delivered to President Obama and President-elect Trump.
On 18 November, the annual Halifax International Security Forum opened in the Canadian city, bringing together serving and former security and foreign policy officials from around the world.
Senator John McCain, a hawkish Republican, was there and was introduced to a former senior western diplomat who had seen the documents, knew their source and thought him highly reliable. McCain decided the implications were sufficiently alarming to dispatch a trusted emissary, a former US official, to meet the source and find out more.
The emissary hastily arranged a transatlantic flight and met the source at the airport as arranged. (The Guardian has agreed not to specify the city or country where the meeting took place.)
The meeting had a certain cold war tradecraft to it, as he was told to look for a man with a copy of the Financial Times. Having found each other, the retired counter-intelligence officer drove the emissary to his house, where they discussed the documents and their background.
The emissary flew back within 24 hours and showed McCain the documents, saying it was hard to impossible to verify them without a proper investigation.
McCain said he was reluctant to get involved, lest it be perceived as payback for insulting remarks Trump had made about him during his rambunctious campaign.
However, on 9 December, McCain arranged a one-on-one meeting with Comey, with no aides present, and handed them over.
“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,” the senator said in a statement on Wednesday morning.
It is not clear what underpinned the FBI’s decision to include a summary of the documents in its highly classified briefing to the president and president-elect and their top staff, before the bureau had completed its investigation.
It may have been as a defensive measure, to prove for posterity that it was not involved in a cover-up, or because its investigators believed them to be credible.
Whatever the motive, it was quickly leaked – first to CNN, which reported on the material on Wednesday. That triggered a controversial decision by BuzzFeed to publish an unredacted version of the documents on its website. It is unclear where the BuzzFeed version came from.
The author of the reports had been insistent on blotting out references to his Russian sources in the copies he gave to the press, including the Guardian, out of fear for their safety.
The unredacted version could have come from the original client, who commissioned the research, or from intermediaries between the counter-intelligence contractor and the client.