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An ex-Russian intelligence officer who worked with Paul Manafort and a Russian escort currently locked up in a Thai jail could be key to answering the question of whether the Trump campaign coordinated with Russia.

On Tuesday night, Special Counsel Robert Mueller filed court documents that raised new questions about contacts between Trump associates and Russia. The memo he submitted related to the impending sentencing of Alex van der Zwaan, a London attorney and Dutch citizen who pleaded guilty to lying to Mueller’s office in November. Van der Zwaan admitted that he misled Mueller’s investigators about his contacts during the fall of 2016 with Rick Gates, Trump’s former deputy campaign manager, and with a Ukrainian business associate working with Gates and Manafort who has been identified in court documents as “Person A.” As Mother Jones reported last month, Person A matches the description of Konstantin Kilimnik, Manafort and Gates’ longtime Ukrainian business partner. On Tuesday, citing a “person with knowledge of the matter,” the New York Times identified Person A as Kilimnik.

Tuesday’s court filing includes major disclosures about Person A. Prosecutors previously asserted he had ties to a Russian intelligence service. But the new filing states that he retained these ties in 2016—that is, during the presidential election—and alleges that Gates was well aware of his associate’s intelligence background. According to van der Zwaan’s sentencing memo, Gates told the Dutch lawyer that Person A was a former intelligence officer with the GRU, Russia’s military intelligence directorate.

That is significant. It means Person A provided a possible connection between the Trump campaign and the Russian intelligence agencies that interfered in the 2016 election. According to the new filing, Gates communicated with Person A in September and October 2016, while Gates held a top position on the Trump campaign.

Assuming that Person A is Kilimnik, Gates wasn’t the only one in contact with him. In the spring and summer of 2016, Manafort and Kilimnik exchanged a series of cryptic emails, since turned over to investigators. The emails appear to relate to a large debt that Manafort owed to Russian aluminum tycoon Oleg Deripaska from a failed joint investment. (Manafort denies owing Deripaska money and claims Deripaska owed him money. Their dispute is the subject of litigation in the Cayman Islands and the United States.) In the emails, Manafort asked Kilimnik if Deripaska had seen press reports on his work for Trump. “How do we use to get whole?” Manafort asked. His question appears to have implied that he hoped to use his ties to the presidential candidate to settle his dispute with Deripaska. He also offered to privately brief Deripaska on the presidential contest.

On July 29, the week after Republican National Convention, where the Trump campaign altered a proposed amendment to the GOP platform to remove language calling for providing “lethal defensive weapons” to Ukranian troops fighting Russian-backed soldiers, Kilimnik told Manafort he wanted to meet in person, according to emails first published by the Atlantic. He said he wanted to discuss “several important messages” from a person he implied was Deripaska, “about the future of his country.” The men met on August 2 at the Grand Havana Room, a cigar bar in New York.

Kilimnik, who has said he has “no relation to the Russian or any other intelligence service,” told the Washington Post last year that his contacts with Manafort in 2016 were private and “in no way related to politics or the presidential campaign in the U.S.,” though he also acknowledged their talks “related to the perception of the U.S. presidential campaign in Ukraine.” A Manafort spokesman suggested their chat was business-related, but Manafort told Politico they discussed the cyberattack on the Democratic National Committee and the release of its emails.

It’s unclear whether Kilimnik conveyed any information from their meeting back to Deripaska, who has denied having any contact with Kilimnik. But three days after the meeting, Deripaska met on his yacht, off the coast of Norway, with Russian Deputy Prime Minister Sergey Prikhodko, a top foreign policy official for Russian President Vladimir Putin. Also on board was a Russian model and escort named Nastya Rybka.

The Deripaska-Prikhodko meeting was recently revealed in a video by Russian opposition activist Alexei Navalny, who relied on Rybka’s autobiography and Instagram posts. Rybka, who claims to be Deripaska’s former mistress, posted video and audio that show her, Deripaska, and Prikhodko on a yacht while the two men audibly discuss US-Russia relations.

Drawing on flight logs, yacht-docking records, photos from Rybka’s Instagram account, and other evidence, Navalny suggests that Prikhodko spent several days on the yacht with Deripaska and Rybka in August 2016. Citing US reports on Manafort’s offer to brief Deripaska, Navalny argues that Deripaska used Prikhodko to pass messages he received from Manafort via Kilimnik on to Putin.

In an odd twist, Rybka was arrested on February 26, along with nine other Russians, in Pattaya, Thailand, and charged with running “sex training” sessions without a license to work. Since then, she has issued pleas to US government officials and journalists offering to provide information on Trump and Russia in exchange for help securing her release.

“I’m ready to give you all the missing puzzle pieces, support them with videos and audios, regarding the connections of our respected lawmakers with Trump, Manafort and the rest,” she says in a video she made on her way to prison. “I know a lot.”

Deripaska, Manafort, and Kilimnik have all denied any involvement in coordination between the Trump campaign and Russia. Rybka’s account is credible enough that it reportedly drew interest from FBI agents, who earlier this month attempted to meet with her. They were rejected by Thailand’s immigration bureau, according to CNN. But the FBI apparently wants to find out if Rybka has information that could crack open the Trump-Russia collusion case.

Read the van der Zwaan sentencing memo here: