Washington (CNN) There is a web of connections between the Trump campaign, the anti-secrecy website WikiLeaks and the public disclosures it injected into the presidential campaign. Federal investigators are examining some of these relationships and whether any of them were part of an effort to coordinate with Russia's election-meddling campaign.

This week, a new thread emerged: Multiple sources confirmed to CNN that the chief executive of Cambridge Analytica, Alexander Nix, contacted WikiLeaks founder Julian Assange in summer 2016 to ask for access to emails from Hillary Clinton's private server. Sources told CNN that he asked for the emails because he wanted to catalog them on a searchable database that would be made available to the Trump campaign or a pro-Trump PAC.

There is no evidence WikiLeaks ever hacked or possessed the emails sought by Nix. But the contact alone raises new questions about Cambridge Analytica's potential role in Russia's efforts to undermine Clinton's campaign.

It's a messy situation and, with so many unanswered questions, such as what Cambridge Analytica knew about Wikileaks' Russia connection when it sought Clinton's missing emails. Still, it's important to consider the broader context. The timeline below tracks how things unfolded, based on all we know.

March 10, 2015 -- Clinton acknowledges using private email server

Soon-to-be Democratic presidential candidate Clinton publicly acknowledged for the first time that she used a private email server during her tenure as secretary of state. She also said she deleted about 30,000 emails about personal matters unrelated to her work for the Obama administration. The deleted emails, which have never seen the light of day, later became a flashpoint of the campaign.

June 16, 2015 -- Trump launches presidential campaign

Trump announced that he is running for president , ending months of rampant speculation. "I am officially running for president of the United States, and we are going to make our country great again," he told a crowd at Trump Tower. When he declared his candidacy, Trump was in the middle of the GOP pack, trailing in polls to former Florida Gov. Jeb Bush, Sen. Marco Rubio and others.

July 2015 -- Russian hackers breach DNC systems

Hackers working for Russian intelligence services "gained access to" the Democratic National Committee's computer networks as part of the Kremlin's campaign to interfere in the 2016 presidential race, according to the US intelligence community assessment that was published after the election.

March 2016 -- Another group of Russian hackers breach DNC systems

Another group of Russian hackers -- separate from the group that hacked the DNC in 2015 -- breached the DNC's computer systems, according to a US intelligence report published after the election. The US intelligence community says Russian intelligence related stolen materials from the DNC to WikiLeaks for public release.

CNN reported this year that Russia gave WikiLeaks the emails through an intermediary.

March 19, 2016 -- Russian hackers gain access to Podesta's emails

Russian hackers gained access to Clinton campaign chairman John Podesta's personal Gmail account by sending a phishing email. The US intelligence community determined in early 2017 that Russian intelligence later gave WikiLeaks hacked emails from Democratic "political figures," an oblique reference to Podesta. CNN reported this year that Russia gave WikiLeaks the emails through an intermediary.

May 3, 2016 -- Trump becomes presumptive Republican nominee

After Trump's victory in the Indiana primary , his main remaining rival, Sen. Ted Cruz, suspended his campaign. By bowing out, Cruz cemented Trump's position as the presumptive GOP nominee.

June 2016 -- Mercer family endorses Trump

The Mercer family, led by Republican megadonor Robert Mercer, begins supporting Trump's candidacy and starts donating to pro-Trump efforts. The family previously backed Cruz in the GOP primaries.

The family financially backs Cambridge Analytica, which started working for Trump over the summer of 2016. Some members of Cambridge Analytica staff were incorporated in the Trump campaign's data operation team.

June 9, 2016 -- Trump tweets about Clinton's deleted emails

Responding to a quip from Clinton, Trump posted on Twitter : "How long did it take your staff of 823 people to think that up--and where are your 33,000 emails that you deleted?"

This tweet came the same day that Donald Trump Jr., Trump campaign chairman Paul Manafort and Trump's son-in-law Jared Kushner met a group of Russians at Trump Tower. Trump Jr. was told before the meeting that one of the Russians would offer incriminating information about Clinton.

June 15, 2016 -- DNC claims it was hacked by Russian intelligence

The DNC and CrowdStrike, a cybersecurity firm it hired to investigate the breaches, revealed publicly for the first time that its servers were penetrated. CrowdStrike said it "identified two sophisticated adversaries on the network" that were associated with Russian intelligence services.

Trump dismissed the notion that Russia was behind the hacks, saying "we believe it was the DNC that did the 'hacking' as a way to distract from the many issues facing their deeply flawed candidate and failed party leader. Too bad the DNC doesn't hack Hillary Clinton's 33,000 missing emails."

July 19-21, 2016 -- Republican National Convention is held in Cleveland

Trump officially became the presidential nominee for the Republican Party during the Republican National Convention, which was held in Cleveland. During the convention, a handful of Trump campaign advisers briefly met with then-Russian ambassador to the US Sergey Kislyak.

Between July 21 and July 31, 2016 -- Cambridge Analytica CEO emails WikiLeaks

Alexander Nix, the chief executive of data firm Cambridge Analytica, emailed Assange seeking access to emails from Clinton's private server so he could turn them into a searchable database for the campaign or a pro-Trump political action committee.There is no evidence that Clinton's deleted emails were ever hacked or that WikiLeaks ever had possession of them.

The Wall Street Journal reported that the email was sent in late July 2016 at some point following the Republican National Convention. This was around the same time Cambridge Analytica started working for the Trump campaign as part of its three-pronged data operation based in San Antonio, Texas.

Right-wing firebrand Steve Bannon was a member of the Cambridge Analytica board when Nix sent the email, according to The New York Times. Bannon later became CEO of the Trump campaign and stepped down from the data analytics company. He took a top White House job in January but left over the summer.

July 22, 2016 -- WikiLeaks releases about 20,000 hacked DNC emails

WikiLeaks posted on its website nearly 20,000 emails that were stolen from the DNC servers. Many of the emails were sent by senior DNC officials. Some of the emails suggested that the DNC favored Clinton over Sen. Bernie Sanders in the primaries, leading to allegations that the primary was rigged.

July 25-28, 2016 -- Democratic National Convention is held in Philadelphia

Democrats held their convention in Philadelphia and formally selected Clinton as their nominee. The gathering was roiled by the WikiLeaks disclosures, which were released days earlier. The emails upset Sanders supporters, and forced DNC chairwoman Rep. Debbie Wassermann Schultz to quit her post

July 25, 2016 -- Trump says it's a "joke" that Russia hacked the DNC

Trump weighed in on the DNC leaks, saying on Twitter : "The new joke in town is that Russia leaked the disastrous DNC e-mails, which should never have been written (stupid), because Putin likes me."

July 26, 2016 -- NYT reports that the US believes Russia hacked the DNC

The New York Times published a report that claimed US intelligence agencies told the White House that they were highly confident that the Russian government was responsible for hacking the DNC. This was the first public report suggesting that the US government agreed with the DNC's assessment.

July 27, 2016 -- Trump publicly asks Russia to hack Clinton's deleted emails

At a news conference , Trump publicly called on the Russian government to hack Clinton's private email server and reveal the deleted emails. Trump's campaign later said his comment was a joke.

"if it is Russia -- which it's probably not, nobody knows who it is -- but if it is Russia, it's really bad for a different reason, because it shows how little respect they have for our country, when they would hack into a major party and get everything," Trump said. "But it would be interesting to see -- I will tell you this -- Russia, if you're listening, I hope you're able to find the 30,000 emails that are missing. I think you will probably be rewarded mightily by our press. Let's see if that happens. That'll be next."

July 29, 2016 -- Trump campaign pays $100,000 to Cambridge Analytica

The Trump campaign made its first of five payments to Cambridge Analytica, cutting a check for $100,000, according to records from the Federal Election Commission.

August 8, 2016 -- Roger Stone says he was in touch with Assange

During a speech in Florida , former Trump campaign adviser Roger Stone claimed to be in touch with Assange and predicted upcoming WikiLeaks releases: "I actually have communicated with Assange. I believe the next tranche of his documents pertain to the Clinton Foundation but there's no telling what the October surprise may be." He later clarified that while he was in contact with Assange, it came through an intermediary.

August 14-17, 2016 -- Stone exchanges messages with Russian hackers

Stone exchanged direct Twitter messages with Guccifer 2.0, a self-proclaimed hacker who published stolen materials from the DNC earlier in the summer. (These DNC releases were separate from the DNC emails published by WikiLeaks.) The Twitter messages were about the contents of some of the stolen DNC materials that Guccifer posted online earlier that summer. Stone denies any wrongdoing or collusion.

Months after these Twitter messages, the US intelligence community announced that Guccifer 2.0 was actually run by Russian intelligence operatives as part of the Kremlin's effort to meddle in the election.

August 18, 2016 -- Trump campaign pays $250,000 to Cambridge Analytica

The Trump campaign made its second of five payments to Cambridge Analytica, cutting a check for $250,000, according to records from the Federal Election Commission.

August 21, 2016 -- Stone predicts upcoming trouble for Podesta

Without specifically referencing emails, Stone predicts that Podesta will soon be in hot water. "Trust me, it will soon the Podesta's time in the barrel," he tweeted . Stone later claimed that he wasn't talking about the upcoming WikiLeaks releases but was alluding to an expose he was planning on his own.

September 1, 2016 -- Trump campaign pays $5 million to Cambridge Analytica

The Trump campaign made its second of five payments to Cambridge Analytica, cutting a check for $5 million, according to records from the Federal Election Commission. The massive payment -- the largest from the campaign to the data firm -- was for a TV ad buy, according to the Wall Street Journal

September 8, 2016 -- Trump questions US intelligence on Russian hacking

In an interview with TV personality Larry King , Trump questioned the recent US intelligence statement that the Russian government was interfering in the 2016 election. "I think it's probably unlikely," Trump said. "I think maybe the Democrats are putting that out, who knows? But I think that it's pretty unlikely."

King's show is broadcast on RT, the Kremlin-controlled news network that targets English-speaking audiences. The US intelligence community says the Kremlin promoted its election-meddling campaign on RT. The Trump campaign said it didn't know King's show was broadcast on the Russian network.

September 9, 2016 -- Stone exchanges more messages with Russian hackers

Stone exchanged direct Twitter messages with Guccifer 2.0. The emails were about the contents of some publicly released DNC materials. Stone denies wrongdoing or collusion. Months after these Twitter messages, the US intelligence community announced that Guccifer 2.0 was actually run by Russian intelligence operatives as part of the Kremlin's effort to meddle in the election.

September 16, 2016 -- Stone predicts WikiLeaks will release Clinton emails

Stone says in a radio interview that WikiLeaks will release new Clinton emails. "I expect Julian Assange and the WikiLeaks people to drop a payload of new documents on Hillary on a weekly basis fairly soon. And that, of course, will answer the question of exactly what was erased on that email server."

October 2, 2016 -- Stone alludes to future WikiLeaks releases

Stone appeared to predict that WikiLeaks would soon post damaging materials about Clinton. He posted : "Wednesday @HillaryClinton is done. #WikiLeaks." Nothing materialized on the date Stone referred to, but two days after that date, WikiLeaks started releasing Podesta's emails.

October 3, 2016 -- Stone again predicts upcoming WikiLeaks releases

"I have total confidence that @wikileaks and my hero Julian Assange will educate the American people soon," Stone tweeted , four days before WikiLeaks began releasing Podesta's emails.

October 5, 2016 -- Stone says "payload coming" from WikiLeaks

"Libs thinking Assange will stand down are wishful thinking. Payload coming," Stone tweeted , two days before WikiLeaks began releasing thousands of emailed hacked from Podesta's email account.

October 7, 2016 -- US formally blames Russia for DNC hacks

The US government broke its silence about the DNC hack. The Office of the Director of National Intelligence, which oversees the entire US intelligence community, announced that the Russian government was behind the hacked emails released by WikiLeaks.

"The US Intelligence Community is confident that the Russian Government directed the recent compromises of e-mails from US persons and institutions, including from US political organizations," the statement said, adding that disclosures on WikiLeaks were consistent with Russian methods.

October 7, 2016 -- WikiLeaks begins releasing Podesta emails

Shortly after the announcement blaming Russia for the DNC hacks, WikiLeaks began posting thousands of emails stolen from Podesta's Gmail account. WikiLeaks went on to release new Podesta emails on a near-daily basis, creating waves of negative headlines for the Clinton campaign in the closing weeks of the election. Trump regularly cited the latest Podesta releases during campaign rallies in October and November. The US government later said Russia was responsible for the hacks.

October 10, 2016 -- Trump says "I love WikiLeaks"

At a rally in Pennsylvania, Trump expressed his admiration for the anti-secrecy website that was publishing dirt on his Democratic opponent, saying "This just came out. WikiLeaks! I love WikiLeaks."

October 12, 2016 -- Stone says he has back-channel communications with Assange

Stone further elaborated on his relationship with Assange in an interview with a local CBS station in Miami. "I do have a back-channel communication with Assange, because we have a good mutual friend," Stone said. "That friend travels back and forth from the United States to London and we talk." Stone says he has never actually met with Assange or spoken with him directly.

October 19, 2016 -- Trump campaign pays $250,000 to Cambridge Analytica

The Trump campaign made its fourth of five payments to Cambridge Analytica, cutting a check for $250,000, according to records from the Federal Election Commission.

November 8, 2016 -- Trump wins US presidential election

To the surprise of most political analysts, Trump beats Clinton to win the US presidential election. His narrow victory in the Electoral College was buoyed by wins in Midwestern states that weren't expected to go his way.

December 12, 2016 -- Trump campaign pays $312,500 to Cambridge Analytica

With the presidential transition underway, the Trump campaign made its final payment to Cambridge Analytica, cutting a check for $312,500, according to records from the Federal Election Commission. In all, the data firm collected more than $5.9 million from Trump's presidential campaign.

January 6, 2017 -- US accuses Russia of meddling in the election