A British Columbia woman has been accused in an unusual federal case of arranging to meet with a man she thought was a divorced father of two in Virginia so she could have sex with his children.

The father was actually an undercover federal agent, and the woman — Theresa Goddard, 45 — was taken into custody Wednesday after she flew into Dulles International Airport. She appeared in federal District Court in Alexandria on Friday after a complaint was filed charging her with attempting to persuade, induce, entice and coerce a minor to engage in sexual activity.

Prosecutors in the Eastern District of Virginia routinely handle child porn and sex cases — and those cases routinely stem from undercover investigations — but they typically do not involve women as the alleged perpetrators.

The investigation began early this month, when an undercover federal agent trolling a Web site for “taboo subjects” found an advertisement posted by a woman seeking an “incest family,” according to the affidavit. The agent from Immigrations and Customs Enforcement’s Homeland Security Investigations directorate sent the woman — who turned out to be Goddard — a message, and the two began corresponding, according to the affidavit.

The agent told Goddard he had two children, making up a 10-year-old daughter named Amy and a 9-year-old son named Mark, according to the affidavit. He said that he was divorced and that his former wife was in jail, according to the affidavit.

For weeks, Goddard sent the agent graphic messages and pictures of herself, court papers say. They eventually agreed to meet in Virginia, and Goddard said she planned on quitting her job at a Canadian lumber mill, the papers say.

When Goddard arrived at Dulles on Wednesday, the agent met her at the baggage claim, hugged her and picked up her luggage from the carousel, according to the affidavit. Soon, though, other agents took her into custody.

In an interview later, she acknowledged coming to meet the agent but said she never talked about having sex with his children, according to the affidavit.

Standing at a table opposite federal prosecutor Matthew Gardner, Goddard did not say anything in court Friday, simply shaking her head no when a magistrate judge asked if she was able to afford a lawyer. She looked down, eyes partially closed, as U.S. marshals led her out of the courtroom.