Conley, who allegedly planned to meet with leaders of the Islamic State in Syria or ISIS, has been charged with aiding terrorism.
The FBI began its investigation in November after Faith Bible Chapel in Arvada reported a young woman spending a lot of time on its campus, taking notes. The church has been alert to visitors behaving strangely since a gunman killed two people in 2007.
In several interviews, Conley told agents she had converted to Islam and openly discussed her beliefs on jihad, which she defined as a fight against "kafir," a derogatory term for non-Muslims.
"To Conley, it is okay to harm innocents if they are part of a target. She felt that if wives, children, and chaplains visiting a military base are killed during an attack, it is acceptable because they should not have been at a legitimate target. She repeatedly referred to US military bases as 'targets,'" an FBI agent said in an affidavit.
During this period, Conley traveled to Texas for a U.S. Army Explorers training program, the FBI said.
Agents tried to convince Conley to give up on violence, the affidavit said. This included suggestions she could work for the Red Crescent, the equivalent in Muslim countries of the Red Cross, or do other humanitarian work.
The FBI also interviewed her parents. John Conley told agents his daughter seemed conflicted about what she believed Islam told her to do but later said her views were "more extreme" than he had realized.
John Conley also said his daughter and the 32-year-old Tunisian man she said she planned to marry asked for his blessing when he interrupted a Skype conversation. He refused.
Conley was arrested after her parents told the FBI she had a one-way ticket from Denver International Airport to Turkey departing on April 8.