The FBI's investigation into Trump and Russia coincided with game-changing, Russia-related events on the campaign trail
Comey told the House Intelligence Committee that the investigation, which "includes whether there was any coordination between the Trump campaign and Russian efforts," is still in its early stages and that he has "no timetable" for when it will conclude.
But the timing of when the FBI opened its investigation coincided with a flurry of events last summer that increased scrutiny on the Trump campaign's friendly attitude toward Russia.
Those included a hack on the Democratic National Committee that was attributed to Russia in late June; an early foreign policy adviser's trip to Moscow in early July; a change in the GOP platform on its policy toward arming Ukraine just before the Republican National Convention; the release of stolen DNC documents from WikiLeaks in late July; and Trump's subsequent public call urging Russia to hack Clinton's email server.
The Democratic National Committee confirmed in mid-June that it had been hacked, and the cybersecurity firm CrowdStrike said that it had concluded with "a very high degree of confidence" that the hack was linked to the Russian government.
Shortly after the DNC hack was made public, Carter Page, then a foreign-policy adviser to Trump's campaign, traveled to Moscow, where he delivered a commencement speech that was highly critical of US foreign policy for the New Economic School. Page served as an adviser "on key transactions" for Russia's state-owned energy giant Gazprom before setting up his own energy investment fund, Global Energy Capital, with former Gazprom executive Sergei Yatesenko.
Page was in Moscow for three days, but it's unclear what he did or who he met with before and after giving the speech. Yahoo's Michael Isikoff, citing a Western intelligence source, reported in September that Page met with Russian oligarch Igor Sechin, the CEO of Russia's state-owned oil company, Rosneft, during his trip. Page has denied those reports, but resigned from the campaign shortly after the report was published.
Later that month, while Paul Manafort was in his position as Trump's campaign manager, an amendment proposing sending "lethal weapons" to the Ukrainian army to fend off Russian aggression - a stance that was generally consistent with the Republican Party's position at the time - was watered down to "provide appropriate assistance." Manafort had advised Russia-friendly Ukraine leader Viktor Yanukovych, whom he helped win the Ukrainian presidency in 2010.
The Ukraine language change was orchestrated by two national-security experts sent to sit in on the subcommittee meeting on behalf of the Trump campaign. That is according to one of the experts, JD Gordon, and the original amendment's author, Diana Denman, who was also in the meeting. As Business Insider has previously reported, the circumstances around the language change are controversial, and there are conflicting accounts as to the reason for the change.
The altered Ukraine policy amendment, with the softer language, ultimately was included in the new GOP platform. A few days later, WikiLeaks began publishing the emails that had been stolen from the Democratic National Committee and Clinton campaign. The timing coincided with the start of the Democratic National Convention the following week.
WikiLeaks didn't reveal its source for the documents. But the emergence of a shadowy figure in early August who called himself Guccifer 2.0 claiming responsibility for the DNC cyberattack added to suspicions that the hacking and disinformation campaign was linked to the Russian government.
Guccifer 2.0, who said he targeted Democrats in the heat of the election last summer, has denied having any links to Russia. But ThreatConnect, a cyber-security firm based in Arlington, Virginia, concluded that Guccifer 2.0 had been using the Russian-based Virtual Private Network service, Elite VPN, to secure their later communications with politicians and reporters.
Former Trump adviser and longtime confidante Roger Stone said he exchanged private messages with Guccifer 2.0 in mid-August that were "short and innocuous."
During a press conference on July 27, Trump called on Russia directly to hack his opponent.
"Russia, if you're listening, I hope you're able to find the 30,000 emails that are missing," Trump said, in an apparent reference to the emails Clinton deleted from her private email server before handing it over to the FBI in late 2015.
"I think you will probably be rewarded mightily by our press," Trump added, referring to the media frenzy that had surrounded WikiLeaks' release of the DNC emails.
On October 7, shortly after an Access Hollywood video surfaced of Trump making lewd remarks about women, WikiLeaks published the first batch of emails hacked from Clinton's campaign chairman, John Podesta.
Seventeen US intelligence agencies concluded in January that Russia interfered in the US election - hacking into the DNC and John Podesta's inbox and leaking the stolen documents to WikiLeaks - to undermine Clinton.
FBI Director James Comey and NSA Director Mike Rogers said on Monday that that assessment had not changed.