Maria Butina, a Russian student whose political activities in the United States came under FBI scrutiny amid an investigation of 2016 election interference, was released from a Florida prison Friday and deported to her home country.

Butina pleaded guilty last year to conspiring with a senior Russian official to access the National Rifle Association and other groups without registering with the U.S. Justice Department, as required by law.

She was released from a federal lockup in Tallahassee, where immigration agents took her into custody. Her attorneys said Friday evening that she had been put on a plane back to Russia.

Butina’s lawyer has complained that her case was stained from the start by anti-Russian sentiment in the midst of the investigation by former special counsel Robert S. Mueller III into Russian interference in the last presidential election. Butina, who studied at American University in Washington, was the first Russian national convicted of seeking to influence American policy in the run-up to that election, though her case was not handled by Mueller, but by local federal prosecutors for the District of Columbia.

At her sentencing in April, Butina said, “though it was not my intention to harm the American people, I did that by not notifying the Attorney General of my actions. I deeply regret this crime . . . Please accept my apology and allow me to begin again.”

In plea papers, Butina said she worked under the direction of Alexander Torshin, a former Russian government official, and with an American political operative on a multiyear scheme to establish unofficial lines of communications with Americans who could influence U.S. politics.

In a statement announcing her deportation, Butina’s attorneys, Robert N. Driscoll and Aldred D. Carry, said: “This closes the book on an inflated prosecution that never should have been brought. Her prosecution, contrary to media reports and government statements early in the case, had nothing to do with espionage, election interference, or anything other than citizen diplomacy. Maria is not a spy. She is not a secret agent. She’s never been employed by the Russian Federation in any capacity.”

Rosalind S. Helderman contributed to this report.