Her contact list included an email account associated with the Federal Security Service, or F.S.B., the Russian intelligence agency that is the main successor to the Soviet K.G.B., and F.B.I. agents who searched her apartment found a handwritten note that read, “How to respond to F.S.B. offer of employment?” She was also photographed with the former ambassador at the Russian Embassy in Washington.

She could easily slip out of the reach of the Justice Department merely by getting into an embassy car, said Erik M. Kenerson, an assistant United States attorney. Russia does not extradite its citizens for prosecution in the United States.

Ms. Butina’s defense lawyer, Robert N. Driscoll, tried to distance his client from Moscow’s interference in the 2016 election. He stressed that Ms. Butina was not indicted by the special counsel investigating Russia’s meddling, Robert S. Mueller III, and should not be lumped with more than two dozen Russians charged with infiltrating the computers of Democratic organizations or illegally using social media to try to influence the election.

“Miss Butina is not a proxy for any of the serious or substantial issues” involving relations between the United States and Russia, Mr. Driscoll said. She “has nothing to do with Mueller.”

In Moscow, Russian government officials said that Ms. Butina, who pleaded not guilty to charges, was a pawn in a much bigger geopolitical game. “You get the sense that someone grabbed a watch and a calculator to determine when the decision on Maria Butina’s arrest should be adopted,” Maria Zakharova, the spokeswoman for the Russian Foreign Ministry, said at a briefing. The charges against her were “deliberately timed,” she said, to undermine the results of Monday’s summit meeting between Mr. Trump and President Vladimir V. Putin of Russia.

The hearing, through which Ms. Butina sat mostly expressionless, also revealed a wider federal investigation into her activities than was previously known. Mr. Driscoll disclosed that investigators for the Federal Election Commission had questioned Ms. Butina about “whether certain donations had been made to a political campaign.” Prosecutors revealed that the Republican political operative from South Dakota who created a company with her in 2016 was the subject of a fraud investigation. Unidentified in the indictment, he is believed to be Paul Erickson, 56, whom Ms. Butina has described as her boyfriend.

F.B.I. agents have been surveilling Ms. Butina, who graduated in May with a master’s degree in international relations, for the past year.