Even though someone has been charged with her murder, volunteers are still not giving up the search.
A group of dedicated volunteers continue to search for the missing 15 year old every Saturday.
Volunteers L.D. Krenzel and Roger Nelson help look for Sierra every Saturday. They spend 20 hours a week helping with the search.
Neither has ever met the missing 15 year old, but now after nearly two years it really doesn't matter.
"More time has passed and more people doubt we'll find her but, that hasn't stopped us. And I think the fact that we're still here may inspire others," Krenzel said.
Roughly 25 people show up to search for Sierra weekly.
And almost as many come to court every time Antolin Garcia-Torres makes an appearance. He's the man accused of kidnapping and murdering Sierra.
Lamar's family and friends have pleaded for the suspect to reveal where her body is.
"It's very frustrating. Why does he not do the right thing? Why does he not alleviate the Lamar's pain?" Nelson said.
Teams have scoured the region over and over again, but still no sign of the teenager.
Sierra disappeared March 16, 2012 as she walked to her school bus.
Police believe Garcia-Torres lured her into his VW Jetta because that's where they found her DNA.
Friends and family gathered Sunday to honor Sierra at Washington High School in Fremont, which is the school she attended before moving to Morgan Hill.
A circular bench has been dedicated to Sierra as a symbol of her last year in high school.
If you would like to be a volunteer to help search for Sierra, click here.