Updated

Paul Manafort, the former Trump campaign chairman who was indicted in October for multiple counts related to Special Counsel Robert Mueller’s investigation and is currently under house arrest, has been working on an op-ed with a colleague “assessed to have ties” to a Russian intelligence service, according to court papers filed Monday by prosecutors working for Mueller.

Manafort, who led Trump’s campaign during the Republican National Convention last year, and the colleague aimed to publish the op-ed under someone else's name and intended it to influence public opinion about his work in Ukraine, prosecutors said. They added that the piece was being drafted as late as last week, with Manafort currently under house arrest.

Prosecutors did not name the colleague but noted the person is based in Russia.

Penning the "ghostwritten" piece appeared to violate a judge’s November admonishment to refrain from speaking publicly, prosecutors said. "The editorial clearly was undertaken to influence the public's opinion of defendant Manafort, or else there would be no reason to seek its publication (much less for Manafort and his long-time associate to ghostwrite it in another's name)."

According to the October indictment, reviewed by Fox News, between at least 2006 and 2015, Manafort and his associate, Rick Gates, acted as unregistered agents of the Government of Ukraine, the Party of Regions, a Ukrainian political party whose leader Victor Yanukovych was president from 2010 to 2014, and the Opposition Bloc, a separate party.

Manafort and Gates generated tens of millions of dollars in income as a result of their work in Ukraine.

The indictment claimed Manafort and Gates laundered the money via multiple U.S. and foreign corporations, partnerships and bank accounts in order to hide Ukraine payments from U.S. authorities.

More than $75 million flowed through offshore accounts, prosecutors said.

They added that they discovered the efforts to publish the op-ed last Thursday and alerted Manafort's attorney, who assured prosecutors that "steps would be taken to make sure it was no longer going to be published."

Fox News’ Brooke Singman and The Associated Press contributed to this report.