Brittany Brown, the young Mountain View resident who made headlines last year when she disappeared for four days after going to a Castro Street nightclub, has been arrested for falsely reporting to police that she was kidnapped and sexually assaulted during the time she was missing.

Brown, who was 18 when the disappearance occurred in September 2008, turned herself in Friday after the district attorney's office issued an arrest warrant for "falsely reporting a crime," which is a misdemeanor. Local police and prosecutors cooperated in the investigation.

"We're glad she was not kidnapped and sexually assaulted," said police spokesperson Liz Wylie. "But it definitely is disheartening for someone to falsely report a crime that is so huge. It really taxes the system."

Brown may have to pay restitution to the police department for "all the time and money spent on this," Wylie said, as officers had been investigating her allegations since last September.

Brown had told police that she was held against her will and sexually assaulted by suspects she could not name in Richmond, where she stayed for the four days she was missing. But authorities have come to believe that Brown fabricated those stories.

"We always assume the victim is telling us the truth," Wylie said. "In this case we developed really good evidence that she was not being truthful with us."

Brown had vanished with an unknown couple after hanging out outside the Monte Carlo nightclub on Castro Street late in the evening of Friday, Sept. 5. Family members said her cell phone was dead and her credit card had not been used. For Brittany to leave without telling anyone was "very out of character," said her mother, Victoria Brown. Posters were put up all over town, and several media outlets reported the story, including the Voice.

"People were really freaked out and worried," Wylie recalled. For four days, she said, police investigators were working extra shifts.

Some city employees also were concerned because Brown worked for the city's "Beyond the Bell Program" for preschoolers, where she did not show up for work.

Brown returned home the following Tuesday, physically unharmed but emotionally wrung out as she was reunited with her family. The event happened to be caught on camera by a KRON TV news crew.

Police quickly made contact with the group of people Brown stayed with in Richmond, but no arrests were made, Wylie said. She added that police always considered the possibility that Brown's story might be false.

"We never let it go because early on we had some evidence to suggest it was false," Wylie said. "Time permitting we've been plugging away at it. We had a lot of evidence to dig up."

Brown is currently out on bail and could face a short jail sentence, restitution or community service.