Police have never found the teen's body. So how will prosecutors proceed with the case?
Seeking the death penalty for 22-year-old Garcia-Torres carries some risk, according to legal analyst and San Jose attorney Steve Clark.
Neither sheriff's deputies nor an army of volunteers has ever found the body of 15-year-old LaMar despite extensive searches that continue even now, two years after her disappearance.
"There's been instances like J.C. Dugard and Elizabeth Smart who were presumed to be dead but were later found alive," Clark said. "And you can believe that the defense is going to hammer that, and they're going to say that the DA's office is overreaching here. If there's a death verdict, that's a verdict that can never be fixed."
The district attorney's office polled members of the LaMar family to discuss the death penalty. Steve LaMar, the teen's father, said there was consensus it was the correct choice.
"In the last month or so we've talked to the DA's office and we've also talked as a family and yeah, that's something that we decided we wanted them to pursue," he said.
Volunteer search leaders expressed hope today that the death penalty might pressure Garcia-Torres to give investigators details where her remains might be found.
"There's a group of volunteers that have come together that have worked and supported the LaMar family for two years," volunteer search leader Debbie Nunes said. "And we consider ourselves extended family, and we will be there for them through the duration of trial, no matter how long it takes."
The decision to seek the death penalty will also pose a challenge to empaneling a jury that is fair-minded about capital punishment.
Law professor Ellen Kreitzberg is a death penalty expert at Santa Clara University Law School.
"Santa Clara County voted, more than 50 percent of the voters in the last election voted to abolish the death penalty in Santa Clara County," she said. "So it is a county that has expressed strong reservations for the death penalty as a general concept."
A hearing will be held on June 11 to set a trial date.
Santa Clara County District Attorney Jeff Rosen released a statement on Monday:
"The grand jury indicted Mr. Antolin Garcia-Torres for attempting to kidnap three women during attempted carjackings in 2009, and for kidnapping and murdering 15-year-old Sierra LaMar in 2012."
"I have decided to seek the death penalty against Mr. Garcia-Torres. I have communicated this decision to the court, the defense counsel and to Sierra's family. Given the facts of this case and after a comprehensive review by a committee of senior prosecutors, I have concluded that this defendant should face the ultimate penalty. Now, we will go forward with the prosecution of all four crimes against the defendant. Upon a guilty verdict for kidnapping and murdering Sierra LaMar, there is an additional hearing for the jury to decide if the death penalty is the appropriate punishment."
"To ensure that the defendant receives a fair trial, I will not be making further comments about my decision at this time, nor am I accepting interview requests from the media on this subject."