We don’t know whether special counsel Robert S. Mueller III has found evidence of collusion or conspiracy between the Trump campaign and Russia.

But for the fourth time, he has proved a Trump aide lied about contacts with Russians.

A judge on Wednesday voided former Trump campaign chairman Paul Manafort’s cooperation deal with the government, agreeing with Mueller’s team that Manafort lied about three matters. In another two matters about which Mueller’s team accused Manafort of lying, the judge did not find “a preponderance of evidence.”

Importantly, included in the three instances in which U.S. District Judge Amy Berman Jackson found Manafort made false statements, one involved his business associate in Ukraine, Konstantin Kilimnik.

The Office of Special Counsel “has established by a preponderance of the evidence that the defendant intentionally made multiple false statements to the FBI, the OSC, and the grand jury concerning matters that were material to the investigation: his interactions and communications with Kilimnik,” reads the ruling from Jackson. Jackson found the evidence lacking on another claim of lies involving Kilimnik.

Kilimnik is an increasingly important figure in the Russia probe. An Aug. 2, 2016, meeting between Manafort and Kilimnik goes to the “heart” of Mueller’s probe, according to Mueller’s team in a recently released court transcript. Previous court filings indicate Manafort shared polling data with Kilimnik and discussed a pro-Russian “peace deal” for Ukraine, whose territory of Crimea was invaded and annexed by Russia in 2014.

Importantly, Mueller’s team has assessed that Kilimnik, who attended a school that produced Russian intelligence agents, continued to have ties to Russian intelligence during the 2016 campaign. It also says Kilimnik, who was born in Soviet-controlled Ukraine, is a Russian citizen.

That translates to the court finding Manafort lied about a contact with a Russian, which wasn’t among the crimes Manafort had previously been convicted of. And that means the courts have found a fourth example of a Trump aide lying about contacts with Russians.

Previously, former Trump campaign surrogate and White House national security adviser Michael Flynn pleaded guilty to lying about his contacts with the Russian ambassador during the transition between the 2016 campaign and Trump’s inauguration. Former Trump lawyer and fixer Michael Cohen also pleaded guilty to lying about contact with the Kremlin during his efforts during the 2016 campaign to secure a Trump Tower in Russia. And among the lies Trump campaign adviser George Papadopoulos pleaded to was lying about contact with a “female Russian national.”

To be clear, not all of these lies are created equal. Flynn’s lie involved conduct after the campaign, suggesting less of a tie to potential campaign collusion. And like Cohen’s and Papadopoulos’s, it was part of a plea deal with Mueller. Manafort’s lie was determined by a judge based upon a preponderance of evidence, rather than via a jury trial.

Other Trump aides have admitted to lying in Mueller’s investigation, too, but not involving specific contacts with Russians. Trump’s longtime political adviser Roger Stone has also been accused of lying about seeking information from WikiLeaks, which the U.S. government says served as a front for Russia’s election interference in 2016.

Yet earlier this week, a Washington Post-Schar School poll showed Americans believe by a margin of 45 percent to 43 percent that Mueller has not proved lies about contacts between the Trump campaign and Russians. He has now effectively proved lies by two Trump campaign surrogates and — perhaps as or more important — the man who headed Trump’s campaign during the late Republican primaries and the early general election campaign.

And Mueller has also now snagged a lie from the man who appears to be an increasingly central figure in the collusion probe. The question has long been why these Trump aides would lie about such contacts, and that intrigue only grew on Wednesday.

This post has been corrected to reflect that Papadopoulos also pleaded guilty to lying about a contact with an unknown Russian.