The family of a missing 14-year old California girl launched an all-out search Sunday morning that extended into the local mountains.

Hundreds of volunteers combed through rugged terrain in search for Amber LeeAnne DuBois, television news station San Diego 6 reported. DuBois was reportedly last seen shortly after 7 a.m. on Feb. 13 while walking to her high school in Escondido, Calif.

The FBI is “providing investigative assistance” to Escondido police, an agency spokesman told the San Diego Union Tribune on Saturday.

Investigators said Amber — who was last seen wearing black clothing and a backpack — talked to a friend on her cell phone as she walked to class that morning. She has not been seen or heard from since, police said.

The teen's father, Maurice DuBois, said reports of a possible sighting of his daughter Saturday were considered unreliable. He said Amber is very structured, and not the type of girl to run away.

The family is hoping that the Tour of California bicycle race — which is expected to draw thousands of spectators to Escondido on Sunday — will heighten public awareness and help in finding Amber.

Local media outlets reported Friday that there may have been an attempted abduction in the same area where Amber was last seen.

The family's private investigator Bill Garcia told San Diego 6 that a woman was almost abducted by a man driving a white utility vehicle in Escondido two weeks before Amber was reported missing — though police have not yet determined a credible link between that case and Amber's disappearance.

Meanwhile, family members have set up a Web site with pictures and contact information for the missing girl, and are pushing for the search to go nationwide.

Click here for more on this story from SanDiego6.com.

Click here for more on this story from 760KFMB.com.

The Associated Press contributed to this report.