Editor’s note: Shortly after this piece was published, the New York Times retracted its Tuesday report that Manafort asked for 2016 polling data to be shared with Russian oligarch Oleg Deripaska. The New York Times issued a correction stating that Manafort asked for the data to be shared with two Ukrainian oligarchs, Serhiy Lyovochkin and Rinat Akhmetov. We have updated this piece to reflect that correction.

Former Trump campaign chairman Paul Manafort’s ties to Russian figures have been simmering at the surface of special counsel Robert Mueller’s probe for more than a year, but Tuesday’s revelation that Manafort stands accused of sharing campaign polling data with a Russian business associate in Ukraine brought one of those relationships more sharply into focus.

The redaction error in a court filing from Manafort’s lawyers more firmly linked Manafort’s time working for Trump to the lobbyist’s longtime business associate Konstantin Kilimnik, who has been linked by Mueller to a Russian intelligence agency as late as 2016.

While running Trump’s campaign, Manafort allegedly asked Kilimnik to pass along election polling data to two Ukrainian oligarchs who had previously funded some of Manafort’s work, Serhiy Lyovochkin and Rinat Akhmetov, according to the New York Times.

The Times initially reported on Tuesday that Manafort asked for the polling data to be shared with Russian oligarch Oleg Deripaska, but the Times corrected that claim on Wednesday.

The improperly redacted sections in Tuesday’s court filing additionally disclosed that prosecutors have pinpointed a meeting between Kilimnik and Manafort in Madrid, where the two supposedly discussed a potential peace plan for Ukraine that would have returned a modicum of power to their former client.

So far, Manafort has mostly faced charges related to the Ukraine lobbying work predating the 2016 campaign that connected him to Kilimnik. He had reached a cooperation deal with Mueller in September, only to torpedo it by allegedly lying to investigators. Yet, Manafort’s links to Russian figures have left lingering questions about whether those ties at all seeped into Manafort’s efforts to put Trump in the White House.

Finally, the allegations revealed in the court filing on Tuesday brought to light more of of Manafort’s alleged actions during the 2016 campaign.

Though Tuesday’s news made public additional interactions between Manafort and his business associate in Ukraine, outside reporting and past court filings have shed light on Manafort’s long history with Kilimnik.

How An Alleged Russian Intel Alum Made It Into Manafort’s Inner Circle

Kilimnik is allegedly a former member of the same Russian military intelligence outfit that is accused of hacking into the Democratic National Committee’s servers and the Clinton campaign during the 2016 election.

By 2005, Kilimnik had spent time at a U.S. pro-democracy organization, and was beginning to work with Manafort on his Ukraine projects, assisting him in his work for Viktor Yanukovych, the Moscow-favored politician who would become president in 2010.

Kilimnik is reported to have worked closely with Manafort throughout his time in Ukraine, even reportedly traveling to the Central Asian nation of Kyrgyzstan with Manafort to ‘strengthen Russia’s position’ in the country.

Manafort and Kilimnik also developed a relationship with a Russian oligarch, Oleg Deripaska, that has drawn the attention of investigators. By the time of the 2016 election campaign, Manafort was indebted to Deripaska.

By 2016, as emails obtained by the Atlantic show, Kilimnik and Manafort tried to use his position at the Trump campaign to offer a way to get back in Deripaska’s good graces.

“How do we use to get whole? Has OVD operation seen?” Manafort reportedly wrote in one April 2016 message to Kilimnik, referencing Deripaska’s initials.

The messages show Manafort using Kilimnik as a link to Deripaska, through the oligarch’s assistant, another former Russian intelligence operative named Victor Boyarkin.

“Tell V boss that if he needs private briefings we can accomodate,” Manafort purportedly wrote in a July 2016 email to Kilimnik, referencing Boyarkin, while he was chairman of Trump’s campaign.

Manafort was still meeting with Kilimnik at that time, once in May 2016 and once more in August 2016 at Manhattan’s Grand Havana Club, a cigar establishment frequented by Rudy Giuliani.

According to Tuesday’s poorly redacted court filing, Manafort and Kilimnik were discussing a potential peace plan for Ukraine — one that would have brought their old client Viktor Yanukovych back to govern the country’s war-torn eastern regions.

“If there’s a serious project that is pro-Ukrainian and can bring peace to this country, then [Manafort] will be back,” Kilimnik told a Radio Free Europe journalist in February 2017, around the time that Manafort’s spokesman says Manafort met Kilimnik in Madrid.

How Kilimnik Put Himself In Mueller’s Crosshairs

It’s unclear at what point Kilimnik became a figure of importance behind the scenes in the federal Russia investigation. But in Mueller’s public court filings, over the course of six months, he evolved from a bit player to facing charges himself.

Mueller first implicitly referenced him when calling out an op-ed Manafort tried to ghost-write, in violation of a judge’s gag order, in December 2017. In court filings, Mueller said that Manafort worked on a draft of the op-ed with “with a long-time Russian colleague … who is currently based in Russia and assessed to have ties to a Russian intelligence service.” Independent reporting quickly identified the colleague to be Kilimnik.

Months later, Kilimnik was involved in yet another scheme that got Manafort in trouble: a witness tampering effort to which Manafort eventually pleaded guilty. While Mueller was seeking to put Manafort in pre-trial detention, he brought obstruction of justice charges against Kilimnik in an indictment that also described Kilimnik’s role in Manafort’s unregistered Ukraine lobbying campaign.

But perhaps the most explosive public details from Mueller about Kilimnik came not in the Manafort case, but in the guilty plea of Alex Van Der Zwaan, a London-based lawyer at a New York law firm who worked on a political project with Manafort in Ukraine. Van Der Zwaan in 2017 lied to the special counsel about his fall 2016 conversations with Kilimnik and Rick Gates, a Manafort business partner who was indicted by Mueller and now is cooperating with the investigation.

A March sentencing memo in Van Der Zwaan’s case described Kilimnik, called “Person A” in the memo, as having “ties to a Russian intelligence service” — ties that continued in 2016, in the FBI and Mueller’s assessment.

According to the New York Times’ new reporting, Manafort and Gates passed along the polling data to Kilimnik in the spring of 2016.