A business associate of a key figure in the investigation into former Trump campaign chairman Paul Manafort has been charged with failing to register as a foreign agent, federal prosecutors in Washington said Friday.
The charge Patten pleaded guilty to - violating the Foreign Agents Registration Act (FARA) by not disclosing lobbying work for Ukrainian politicians - is similar to one of the core allegations against Manafort in his upcoming trial.
The criminal charging document does not name Manafort or any of his colleagues in the United States and Ukraine, though Patten may be connected to those efforts.
Along with being an associate of Manafort's and an employee at the OR office of Cambridge Analytica's parent company, Patten was also an old friend and regular business associate of Konstantin Kilimnik, a man suspected of having ties to Russian intelligence.
Manafort, who was sacked as Trump's campaign chairman in August 2016, was convicted by a federal jury in Virginia on tax and bank fraud stemming from his work between 2010 and 2014 for the pro-Russia Ukrainian political party Party of Regions and then-President Viktor Yanukovych. He also has been charged, along with Kilimnik, with obstruction of justice through alleged witness tampering.
Mr. Kilimnik is not named in Friday's charging papers against Mr. Patten, but is identified as "Foreigner A", a Russian national who formed a company in the United States with Mr. Patten.
The charge, which carries a maximum of five years in prison, was brought by the US Attorney for the District of Columbia and the Justice Department's National Security Division, which started investigating Patten after a referral from Mueller.
W. Samuel Patten entered his plea in federal court in Washington, copping to disclosure crimes as prosecutors laid out his business connections to Manafort, the Ukrainian, and an American with ties to Russian intelligence.
Patten's attorney Stuart Sears declined comment after the Friday court appearance.
U.S. District Judge Amy Berman Jackson told Patten that she couldn't provide any estimate of his potential sentence because U.S. sentencing guidelines don't have a section for violations of the Foreign Agents Registration Act.
Patten's company received more than $1 million for its consulting work with the party.
After the congressional testimony, Patten then destroyed documents relating to his foreign work.
Patten worked for multiple political parties and office-holders in Ukraine, according to his website. Patten told the Daily Beast earlier this year that he worked with the company in its 2014 USA elections work and on "several overseas campaigns". His sentencing date has not yet been scheduled. Patten worked with Manafort and on Ukrainian campaigns, and reportedly worked on microtargeting operations with Cambridge Analytica.
Patten's work continued through Donald Trump's surprise election win.
As CNN producer David Gelles noted, Patten was charged for acting as an unregistered foreign agent for Russian Federation and Ukraine between 2014 and 2017.
In an 2017 interview with The Washington Post, Patten said he met Kilimnik in Moscow more than 15 years ago, when Kilimnik was an employee of the International Republican Institute, a pro-democracy group affiliated with the Republican Party.
But Patten's ties to Kilimnik are more concrete.
Brooke Singman is a Politics Reporter for Fox News.