The entire time, investigators have called this a missing persons case, since they weren't sure if Sierra LaMar simply ran away. Now detectives think she may have voluntarily left with someone and that someone is stopping her from coming home.
"More time means you wonder what's happening with her, where she is, and does someone have her?" said Steve LaMar, Sierra's father.
Sierra's parents are trying to keep their minds from wandering to a dark place, especially now that investigators have re-classified the 15-year-old's case. Now they say, there's a chance, someone is holding her against her will.
"Could be she voluntarily left the home and then at some time soon after, contacted somebody and or came into contact with somebody that now has involuntarily kept her missing," said Santa Clara Sheriff's Sgt. Jose Cardoza.
The FBI continues to focus on the area surrounding Sierra's home. And sources say family members have completed several interviews and passed polygraph tests.
Meanwhile, the first massive volunteer search effort took place in fields, reservoirs, and parks. For many, knowing Sierra didn't run away, reaffirms their dedication.
"It makes me want to be out there and be involved with our community here and be arm and arm with them and say, 'You know what? Enough is enough, these are our kids, don't touch them,'" said Connie Meck, a Morgan Hill volunteer.
"Because of this response and the community coming together, I know Sierra's chances of having a safe return is increasing," said Marlene LaMar, Sierra's mother.
Volunteers scoured property near Calero Reservoir in Santa Clara County. By mid-afternoon, nearly 600 people had shown up offering to look for evidence in Sierra's disappearance. Organizers are calling the community response unprecedented.
There was something about the length of the line for volunteers on a weekday morning that was both overwhelming and reassuring. "I think that this is very uplifting and very hopeful for the family to actually be a witness to what this community is doing," said Search Operations Director Brad Dennis. More than 500 volunteers showed up to register at the Find Sierra Search Center in Morgan Hill. "She's someone's sister, someone's daughter, someone's best friend," said searcher Jess Anguiano. "It hits home."
The massive community volunteer search effort is the latest step forward in the mysterious disappearance of Sierra. Authorities are now calling her case a "probable abduction." The KlaasKids Foundation gave each volunteer team a GPS device and a ground search locations. "There's no ambiguity about who's going where and what they're doing. It's really very advanced. And then, we turn all of that information over to law enforcement at the end of the day," said Marc Klaas.
One team tackled the Calero County Park area while other groups systematically made their way though fields off Santa Teresa Blvd. ABC7 first spoke with Krystal Thomas last week. She was hanging up Sierra flyers at her Morgan Hill business. On Tuesday, her team made note of some rope, a sock, and a boot. "We're just marking anything that looks new or out of place, and hoping that it leads to bringing her home," she said.
No one has seen Sierra since March 16, but in addition to the official investigation taking place near her home, there are volunteers and Midsi Sanchez, offering hope. She escaped from her kidnapper in 2000. "I just want them to know and believe that there is a possibility that Sierra can come home, because it has happened before. It's happened to me and many others," she said.
The sheriff's office released a statement saying they believe the person responsible for Sierra's disappearance may not live in Morgan Hill, but they believe that person is familiar and comfortable with the area.
The search center will reopen at 8 a.m. and volunteers will work out of here until Sunday. Tuesday night, the family set up a Sierra LaMar donation fund at all Chase Bank locations.