Special counsel Robert Mueller appears to be nearing completion of his investigation of ties between Russia and Donald Trump’s presidential election campaign. And newly released transcripts of a recent court hearing reveal one telling focus of the probe.

In August of 2016, then-Trump campaign chairman Paul Manafort and his deputy, Rick Gates, met with a Russian employee of their international consulting business, Konstantin Kilimnik, at an exclusive cigar club in Manhattan.

“It was at that meeting,” reports the Washington Post, “that prosecutors believe Manafort and Kilimnik may have exchanged key information relevant to Russia and Trump’s presidential bid.

“The encounter goes ‘very much to the heart of what the special counsel’s office is investigating,’ prosecutor Andrew Weissmann told a federal judge in a sealed hearing last week.”

Weissman told Judge Amy Berman Jackson that one of Mueller’s key missions is to evaluate contacts between Trump associates and Russians, especially political operatives like Kilimnik.

“During the hearing,” reports the Post, “the judge also appeared to allude to another possible interaction” at the 2016 meeting: “a handoff by Manafort of internal polling data from Trump’s presidential campaign to his Russian associate.”

The judge also noted that the three men left the club by separate doors.