A 19-year-old woman has been arrested for allegedly trying to provide support to Islamic State of Syria and the Levant (Isis), it has emerged.
Shannon Maureen Conley, from Denver, was arrested in April as she attempted to board a flight, according to recently unsealed court documents.
She told officials she was flying to Turkey and then to Syria to meet a suitor she met online.
The man, a Tunisian, claimed to be an active member of Isis.
According to a criminal complaint filed with the US District Court in Colorado, Ms Conley attended a military tactics and firearms training course with the US Army Explorers earlier in the year.
She allegedly planned to use the training to help Isis fighters through the man she met online, who shared her "view of Islam as requiring participation in violent jihad against any non-believers", the complaint said.
Officials began to investigate Ms Conley after the pastor at Faith Bible Chapel in Arvada, Colorado, alerted local police and the Colorado FBI to a woman suspiciously taking notes of the layout of the church's campus.
The church had been the scene of an earlier deadly shooting in 2007.
According to court documents, Ms Conley, a Muslim convert, told investigators she had initially taken classes at the church to learn about different religions.
But church staff followed her around, she told officials, and she did not like the church's vocal support for Israel.
She allegedly told investigators: "If they think I'm a terrorist, I'll give them something to think I am," according to the complaint.
Federal agents encouraged Ms Conley's parents to get her to meet elders at her mosque to find more moderate options. Officials said her parents were apparently unaware of her extremism.
Her father told an official he had declined a Tunisian man's request for a blessing to marry his daughter, and the couple were surprised by his refusal.
Four days before her arrest, she allegedly told agents that nothing they could do would change her mind to fly to Turkey.
They stopped her as she was walking on to the plane.