SAN JOSE — More than five years after Sierra LaMar vanished while on her way to her school bus stop, a jury on Monday concluded that her killer must spend the rest of his life in prison without the possibility of parole.

The result fell short of what prosecutors and Sierra’s family had wanted: the death penalty for 26-year-old Antolin Garcia-Torres. But the same jury that convicted him rejected that option — a result one expert said was not surprising given Sierra’s body hasn’t been found.

Garcia-Torres will be sentenced in mid-September in Santa Clara County Superior Court by Judge Vanessa A. Zecher, who presided over the whole four-month trial.

Prosecutors had argued the jury should opt for death because it was the only punishment that could capture the horror of the 15-year-old’s final moments. And many in the packed courtroom anticipated that would be the verdict because the same jury — which took only two days to find Garcia-Torres guilty — also reached a decision on the penalty in the same short amount of time.

But without Sierra’s body, a murder weapon or witness statements, the prosecution argument proved unpersuasive. The defense reminded the jury that other girls who went missing and were believed dead instead turned out to have been kidnapped and later were found alive, including California’s Jaycee Dugard.

When the clerk announced the verdict, Sierra’s father Steve LaMar, bowed his head, but none of Sierra or Garcia-Torres’ relatives reacted audibly. Sierra’s family supported District Attorney Jeff Rosen’s decision to pursue the death penalty.

Outside the Hall of Justice, Steve LaMar thanked jurors but acknowledged feeling let down.

“I’d be lying if I said I wasn’t disappointed,” he said. “(Garcia-Torres) will be able to breathe, to eat, to see his family. We’ll grieve the rest of our lives.”

Relatively few “no body” homicide cases go to trial, but prosecutors nationwide have won nearly 90 percent of the 480 that have since 1819, according to former federal prosecutor Tad DiBiase, who maintains a database. However, only 33, or about 7 percent, have resulted in a death penalty sentence, he said. No figures are available for how often it was sought.

“Death penalty sentences in no body cases are rare,” DiBiase said. “When you don’t have a body, the jury is still a little reluctant to take that extra step.”

Last month, the jury convicted Garcia-Torres of abducting and killing 15-year-old Sierra as she made her way to her school bus stop in a semi-rural area north of Morgan Hill early one morning in 2012.

The panel also convicted him of the 2009 attempted kidnappings of three other women from grocery store parking lots, which the prosecution portrayed as a “training ground” for Sierra’s abduction and murder three years later.

In a brief statement, defense attorneys Al Lopez and Brian Matthews said they continue to believe in Garcia-Torres’ innocence and plan to file a motion asking the judge for a new trial.

“We are thankful for the jury’s life verdict,” they said.

Despite the considerable expense the county incurred by seeking the death penalty, District Attorney Rosen made no apologies Monday for pursuing it, saying it is appropriate in crimes that are “unspeakably evil.” The Alternate Public Defender’s Office estimated the case cost nearly $1 million more than it would have otherwise, including for the two lawyers assigned to the case and the many paid experts who were consulted. Copying costs alone for documents and transcripts cost tens of thousands of dollars.

“While Sierra was your daughter,” Rosen said, turning to address Marlene LaMar, “she has become our daughter too. The jury made it so the defendant will die in prison and never take a free breath again in his life.”

Sierra’s mother alluded to the possibility that Garcia-Torres would reveal the whereabouts of Sierra’s remains.

“There are life-changing consequences for evil actions,” Marlene LaMar said. “He can start to make it right by being honest with our family, his family and God.”

Even if the jury had opted for death, Garcia-Torres wasn’t likely to be executed for ages, if ever. In the past four decades since 1976, only 13 people have been executed in California, the most recent in 2006.

The last time a Santa Clara County jury sentenced someone to die was six years ago, when Melvin Forte was given the death penalty for the 1981 kidnapping, rape and murder of German tourist Ines Sailer in San Jose. Of the 747 killers now on death row in San Quentin prison, just 26 — 3 percent — were sent there by Santa Clara County juries.

Garcia-Torres’ attorneys argued Sierra is not dead, and suggested she may have run away without a trace because she was unhappy about her recent move from Fremont with her mother and mother’s boyfriend.

Prosecutors relied on physical evidence, including what crime lab analysts said was traces of Sierra’s DNA in Garcia-Torres’ car. Among several spots in the car, her DNA was found on a single strand of her hair on a rope in the trunk, while his DNA was on her pants found abandoned in a field. He told police they never met.

Garcia-Torres’ fingerprint also was found on a battery found on a stun gun dropped by the assailant in one of the supermarket attacks.

Lopez said the fingerprint could have gotten there because Garcia-Torres worked at the Morgan Hill Safeway where the battery was purchased.