The woman, Elena Alekseevna Khusyaynova, 44, of St. Petersburg, was involved in an effort “to spread distrust towards candidates for U.S. political office and the U.S. political system,” prosecutors said.

Ms. Khusyaynova managed millions of dollars for a company owned by Yevgeny V. Prigozhin, a Russian oligarch who was previously indicted on charges of interfering in the 2016 presidential election, to finance foreign influence activities directed at the United States. Some of the money was spent on advertising on social media in the United States, buying internet domain names and “promoting news postings on social networks.”

The conspirators seized on divisions in American politics, prosecutors said, including immigration, guns, race relations, women and even the debate over the protests by National Football League players during the national anthem. They adopted a variety of ideological perspectives, writing on varied topics and from opposing views, prosecutors said. No one was named in court papers besides Ms. Khusyaynova.