WASHINGTON -- A man charged in special counsel Robert Mueller's Russia investigation has pleaded guilty Tuesday to lying to investigators in the Russia probe. Mueller's office charged Alex Van Der Zwaan, a former associate of the firm Skadden, Arps, Slate, Meagher & Flom, who appeared before Judge Amy Berman Jackson in Washington, D.C., Tuesday afternoon.

A document detailing the charge in D.C. federal district court said that Van Der Zwaan on November 3, 2017 "did willfully and knowingly make materially false, fictitious, and fraudulent statements and representations" as he answered questions from the FBI regarding his work as an attorney at a law firm doing work for Ukraine.

The document says he lied about his communication in August 2016 with Rick Gates, a former Trump campaign adviser and associate of ex-campaign chairman Paul Manafort. Gates is expected to plead guilty in a deal with special counsel Robert Mueller, according to sources familiar with the negotiations, CBS News' Paula Reid reports. Gates, 45, was indicted by a federal grand jury in October on eight counts including fraud and money laundering as part of the special counsel's probe into ties between the Trump campaign and the Russian government.

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Zwaan had been accused of saying that the last time he communicated with Gates was in mid-August. But the government found he lied and had encrypted message conversations in Setepmber 2016, including a phrase in Russian that translates to "essentially the tip of the ice berg." Zwan had also been accused of lying about an email exchange between himself and someone called "Person A" who remains unidentified.

Zwaan faces up to five years in prison and an up to $250,000 fine. Zwaan, according to his attorney, has been in the U.S. since November.

This comes days after Deputy Attorney General Rod Rosenstein announced Friday the indictment of 13 Russian nationals and three Russian entities accused of breaking U.S. laws to interfere with the 2016 presidential election. The defendants conducted information warfare against the U.S., Rosenstein announced Friday. Twelve of the individual defendants worked at various times for Internet Research Agency, based in St. Petersburg, he added.

— CBS News' Paula Reid, Clare Hymes and Kathryn Watson contributed to this report.