March 24, 2012— -- After a week of few leads and dashed hopes, missing teen Sierra LaMar's family, friends and classmates gathered at a candlelight vigil for the Morgan Hill, Calif., girl who has been missing for nine days.
"We want you to come back home. We know you will find your way back to us," Sierra's mother, Marlene LaMar, said among the flickering candles and teary-eyed supporters Friday.
The FBI set up a roadblock where LaMar would usually board her bus and is stopping drivers who pass through, hoping someone will provide a clue that could help bring Sierra home.
Marlene LaMar said Sierra's bus driver told her she never boarded the bus the day she disappeared.
Marc Klaas, whose daughter Polly was kidnapped and murdered in 1994, is also on the case and has helped LaMar set up a search center.
The 15-year-old was last seen on March 16 as she headed off to school from her Morgan Hill home.
Police found a bag belonging to the teen two days later, discarded near an intersection close to her home.
Santa Clara County Sheriff's Sgt. Jose Cardoza said her Juicy brand bag contained a neatly folded pair of pants and a T-shirt, but that the evidence provided no clues about whether Sierra was abducted or ran away.
Cardoza said police were treating her disappearance as a missing person's case. "There is no information leading us to believe she purposely ran away," he said. "On the other hand, we don't have information or evidence associating a crime with her being missing."
Investigators found Sierra's cell phone on the side of a road in the opposite direction of her bus stop a day after her disappearance. The charger for the teen's cell phone was found in her room at home, and the phone looked as if it had been tossed.
Authorities said the phone yielded no clues, nor did investigators find any helpful clues on her computer.
"I can't imagine Sierra without her cell phone," her mother said. "That's when it became a harsh reality."
Sierra's father, Steve LaMar, said he had no reason to believe Sierra was planning to run away.
He talked to her the day before she was reported missing, and she was "happy, talking to me about homework.
"She was asking me to make an appointment so she could dye her hair," Steve LaMar said. "She wouldn't miss that appointment — if you knew my daughter."
Sierra LaMar's parents reached out to her friends, and grew more anxious when one friend said she wasn't in class earlier that day.
They decided to contact authorities around 5 p.m., after her high school sent them an email saying Sierra hadn't shown up for school that day.
Sierra LaMar's parents are divorced, and she lived with her father in Fremont, Calif., until October, when she moved in with her mother and transferred to Sobrata High School in Morgan Hills.
ABC News has learned that Steve LaMar is a registered sex offender and is currently on probation for committing lewd and lascivious acts with a child under 14 years of age. Police have emphasized that Steve LaMar is not a suspect in the investigation.
Police have questioned students at both Sierra's current high school and the previous school she attended in Fremont, Cardoza said. They have interviewed more than 100 people and have broadened the investigation to include all known sex offenders in the immediate and broader area of the teen's home.
But for now, it's a race against time and friends and family can only hope for the best but admit they fear the worst.
"It's been so long, every day we wonder if she's ok," friend Shanice Washington said. "Everyday it gets harder."