News Monday that former Trump campaign adviser George Papadopoulos had pleaded guilty to lying to the FBI during its probe of Russian meddling in the 2016 election carried with it a juicy question: Who on the Trump campaign corresponded with Papadopoulos regarding his efforts to pursue meetings with Kremlin-linked Russians?

Court documents unsealed Monday described Papadopoulos’ relationship with three individuals who claimed to have ties to the Kremlin, including one whom the erstwhile Trump campaign aide incorrectly believed to be Vladimir Putin’s niece and one who promised “dirt” on Hillary Clinton, including “thousands of emails,” months before hacked Democratic emails had been published by Wikileaks. Papadopoulos lied about the nature of his communications with the individuals, which he ultimately admitted to federal investigators.

The court documents detailed Papadopoulos’ communications with other campaign staff — who remain nameless in the documents — about potential meetings between campaign officials, including Trump himself, and Russians.

According to the court documents, Papadopoulos emailed someone referred to as “another high-ranking Campaign official” in May 2016 with the subject line “Request from Russia to meet Mr. Trump.” and said: “Russia has been eager to meet Mr. Trump for quite sometime and have been reaching out to me to discuss.”

A footnote on that paragraph notes that “the official forwarded defendant PAPADOPOULOS’s email to another campaign official,” without Papadopoulos included, stating: “Let[‘]s discuss. We need someone to communicate that DT is not doing these trips. It should be someone low level in the campaign so as not to send any signal.”

In August, the Washington Post published the same email mentioned in the court document: “the high-ranking Campaign official” is Paul Manafort, according to the Post’s report, and “another campaign official” is his longtime deputy and business partner, Rick Gates. Citing an unnamed “Trump campaign source,” Yahoo News also reported Monday that Manafort was the source of the email urging Gates to find “someone low level” to deal with the situation.

Both Manafort and Gates surrendered to the FBI on Monday, and the pair pleaded not guilty to 12 counts against them, including Foreign Agents Registration Act violations and money laundering.

Another mysterious unnamed figure in the court documents: one unnamed “Campaign Supervisor” who told Papadopoulos in August 2016 that “I would encourage you” to meet with the Russian officials.

According to Yahoo News’ campaign source, the “Campaign Supervisor” is Sam Clovis, the non-scientist currently nominated by the Trump administration to be the USDA’s chief scientist. Clovis, an Iowan conservative radio host and Tea Party activist, joined the Trump campaign in August 2015 as a co-chair and policy adviser.

In the Washington Post’s August report on Papadopoulos’ emails, Clovis expressed wariness a few months earlier, in March 2016, at the prospect of what Papadopoulos described as “a meeting between us and the Russian leadership to discuss US-Russia ties under President Trump.”

According to the Post, Clovis said he thought “NATO allies should be consulted before any plans were made.”

In May, Clovis was similarly circumspect when responding to a forwarded email from Papadopoulos, from an official in a Russian government-funded organization who proposed the Trump campaign write a formal letter outlining a potential trip by Trump to Russia.

“There are legal issues we need to mitigate, meeting with foreign officials as a private citizen,” Clovis wrote.