Maria Butina/photo by the Associated Press

Marina Butina, the Russian woman accused of cozying up to conservatives in the lead-up to the 2016 U.S. election, pleaded guilty Thursday to conspiring to work as a Russian agent as details of her cooperation were unveiled in Washington, D.C., federal court.

Butina admitted to working in the U.S. on behalf of the Russian government without notifying the Justice Department. She admitted she worked at the behest of a Russian official—believed to be Alexander Torshin, the Russian central bank's deputy governor—as she sought to infiltrate Republican political circles, including the National Rifle Association.

Court documents show that during that time, she worked alongside and was romantically involved with a man believed to be Paul Erickson, a Republican operative with ties to the NRA. Neither Torshin nor Erickson have been identified by name in court papers or proceedings.

Butina will cooperate with federal authorities as part of her guilty plea, according to her attorney, Robert Driscoll of McGlinchey Stafford.

Thursday's plea caps the monthslong legal saga for Butina, who was arrested and charged in July on suspicions that she operated in the U.S. as a Russian spy. Butina, a gun rights activist in Russia, was living in Washington, D.C., while attending graduate school at American University.

Authorities detailed in court papers Butina's efforts to ingratiate herself with Republican circles, painting her interests as more than extracurricular: she, with the help of Erickson, developed ties with NRA officials to advance Russian interests. Butina was also involved in an effort to set up “friendship dinners” aimed at strengthening U.S.-Russian ties.

Butina worked under Torshin's direction to create a back channel of communications with Americans, which the U.S. in July filings said “could be used by the Russian Federation to penetrate the U.S. national decision-making apparatus to advance the agenda of the Russian Federation.”

Prosecutors on Thursday did not resurface some of the more salacious allegations they've made against Butina. Court filings did not include prosecutors' earlier accusation, which has been since retracted, that Butina sent messages offering sex for a job, an allegation that spilled into the press and drew the admonishment of U.S. District Judge Tanya Chutkan, who said it was “apparent on their face” that Butina's statements were jokes.

Depending on the outcome of Butina's cooperation, she is expected to face up to six months in prison. Butina, who was detained in a Washington, D.C., jail after being described as a flight risk in July, could also face deportation after finishing any possible prison sentence.

Chutkan did not set a sentencing date Thursday. A status hearing was set for Feb. 12.