July 8, 2004 -- Six years ago, Kenny Dunn says, he had one of the best nights of his young life. A high school sophomore, he was at the Sadie Hawkins dance with his first love, a mysterious girl named Brianna Stewart, and their romance was blossoming.
"I kissed her on the dance floor, and I told her I loved her," Dunn remembered. "And she told me she loved me, too. That was one of the greatest nights of my life. … Everything I felt for her was so wonderful, so pure."
Stewart had shown up in Vancouver, Wash., the year before, telling people she was a 15-year-old homeless runaway. She turned to a local church for help, and two members, Randy and Debbie Fisher, offered her a home.
The Fishers asked about Stewart's past, but she told them she had no personal records because she was a runaway. Administrators at Evergreen High School allowed her to enroll, even though she did not have an academic record.
In her girlish pigtails and trademark overalls, Stewart made friends at the school, who called her "Brie." She joined the tennis team and earned a part in the school play.
"I was so amazed by her because she had all these stories to tell about how she lived on the street and that she had trekked so far across the country," Dunn said. "I thought she was the most incredible thing."
Dogged by Questions About Their Past
However, some questions about her background continued to follow Stewart as she progressed at Evergreen High School. She told her friends dark stories about running away from a stepfather who was a satanic high priest and who had subjected her to ritual abuse, but remained vague on the details.
A visit to the dentist sparked some speculation that Stewart was older than she claimed. During a dental checkup, the dentist observed the healing of her gums over her wisdom teeth was so complete that he thought she was much older than 16, as she now claimed to be. He told Stewart's caseworker about his suspicions.
News of the dentist's suspicions traveled fast through the tight-knit Vancouver community that had been helping Stewart. Dunn learned about it from the Fishers and decided to confront her with the information.
When Dunn asked Stewart whether she was older than 16, she blew up at him, he says.
"She screamed at me. 'How dare you make these allegations at me?' " he said. "I just stopped right there. I wanted to keep our relationship so much that I shut my mouth and never said another word about anything again."
Desperate to Establish Brianna Stewart
Although Stewart denied the dentist's allegation that she might be older, she had no way to prove it. As a runaway, she had no personal records — no birth certificate, no Social Security card, no shred of evidence of who she was. Although she remembered the names of her mother and her stepfather, efforts by caseworkers and friends to track them down were fruitless.
In 2000, as graduation from Evergreen High School neared, Stewart became desperate to establish her identity and get some kind of official identification. Without it, she could not get a job, rent an apartment, or even enroll in college.
Stewart wrote letter after letter to social workers, victim's groups, even the governor, detailing her horrific past and pleading for help in securing an official ID card. She even filed suit against the Washington state Bureau of Vital Statistics, demanding that they issue her a birth certificate.
All these efforts failed. Finally, she decided to submit her fingerprints as the first step of an official application for a Social Security card.
That's when Stewart's life in Vancouver began to unravel.
Exposed — and a Community Shocked
When Stewart submitted fingerprints, an FBI check matched her prints with someone named "Stephanie Williams," who had been arrested in Pennsylvania five years earlier for filing a false police report. "Williams" had told police at the time that she was on the run from a cult and pornography ring — a story that sounded very familiar to the Vancouver police officers who had met Stewart.
Following a trail from town to town, Vancouver police concluded that Stewart had used several aliases in at least eight states over a 15-year period. In North Carolina, she was known as Emily Kara Williams; in Texas, she used the name Cara Williams; in Idaho she was Cara Davis and Cara Lewis; in Oregon she was known as Keili Smitt.
Everywhere she went, Stewart posed as a teenage runaway, sought shelter at a church, told tales of cult rituals, abuse and pornography.
Ultimately police traced Stewart back to the name on her birth certificate: Treva Joyce Throneberry, born May 18, 1969, in Electra, Texas.
In May 2001, four years after arriving in Vancouver, Stewart was arrested for perjury and theft, and her bizarre story of deception made headlines in the small town and nationwide. Vancouver residents and Stewart's friends — some of whom had gone away to college — were stunned.
"On the refrigerator was a note that says, 'Ken, your Mom called. … Brie's been arrested. She's 31 years old,' " Dunn recalls. "What the heck happened to me?, I thought. This person who I gave everything to doesn't exist. It's a ghost. I dated a ghost."
An Easy Conviction
At her trial, Stewart furiously denied that she was Treva Throneberry, despite the fingerprints, various personal ID cards and photos that investigators and prosecutors presented as evidence. She insisted she was Brianna Stewart.
Kenneth Muscatel, a mental health expert who examined Stewart but did not testify at the trial, said she appeared to be trying to reject her past.
"There's a sense of being empty inside, so empty inside that being yourself is undesirable, and making a new persona is desirable to being yourself," he told Primetime.
Stewart fired two court-appointed attorneys, turned down plea bargain offers, and chose to represent herself at trial. It took only four hours for jurors convict her on all seven counts of felony theft and perjury. She was sentenced to three years in a state prison.
Treva Throneberry Denied
Released in June 2003 after serving two years and 3 months of her sentence, Stewart is now a free woman. She continues to insist she is a 21-year-old named Brianna Stewart, and not 34-year-old Treva Throneberry.
Stewart told Primetime that the DNA tests and fingerprint results proving her true identity are all mistaken. (DNA evidence was never presented at Stewart's trial because the prosecution didn't want to pay for the expert who conducted the testing to fly in from Baltimore. The prosecution also felt it had enough evidence in the photos, personal identification cards and fingerprints.)
Stewart claimed that the tests had produced false matches because the Throneberrys had "altered blood" in their veins because family members had undergone treatment for cancer. "When persons have recent blood transfusions, and cancer treatments, it does alter the chemistry of the blood somewhat," she said.
However, Treva Thornberry's father, whose blood was used for the DNA test, had no transfusions or cancer therapy.
"I'm not Treva Thornberry," Stewart said. "I just want to reiterate that I am not, no matter how much that family wants to suddenly produce their family member, no matter what they do, what they say, I am not Treva Throneberry nor will I ever be Treva Throneberry. Because you can't make another person into somebody else. You just can't."
This story originally aired on September 25, 2003.