Sierra LaMar: With no body, DNA is star of the trial – The Mercury News

SAN JOSE Lawyers in the capital trial of the man accused of killing missing teen Sierra LaMar bored into the evidence at the heartofthe case Wednesday, arguing over whether itproves the girl whose body hasnt been found was kidnapped and slain.

Prosecutor David Boyd is relying heavily on DNA to prove his theory that Antolin Garcia-Torreskidnapped and killed Sierra. The 15-year-old disappeared nearly five years ago on her way to her school bus stop in the rural community north of Morgan Hill.

Garcia-Torres, now 25, has pleaded not guilty to those counts and to charges that he tried to kidnap three women from Safeway parking lots in Morgan Hill three yearsearlier, in 2009. If he is convicted, he could be sentenced either to death or life in prison without parole. However, if he is acquitted, he cannot be tried again, even if Sierras body is found or other evidence surfaces.

Crime lab analysts have been testifying for days in Santa Clara County Superior Court about finding DNA consistent with Garcia-Torres on Sierras pants and DNA consistent with hers in his 1998 red Jetta, including on a cloth glove in his trunk. The findings are considered crucial because Garcia-Torres claimed they never met.

But defense lawyers Bicka Barlow, Al Lopez and Brian Matthews dispute the findings. They allege sheriffs deputies mishandled and contaminated the evidence. They also contend that the crime lab, which issupervised by the District Attorneys Office, failed to conduct a thorough, impartial investigation.And they say that the science is evolving so rapidly it would be wrong for the jury to view DNA results as solid proof.

For instance, crime lab analyst Michelle Bell testified in minute detail this week about the five separate samples of one sperm each she found on Sierras pants and on one of her socks. Bell said the results were inconclusive for four of the sperm. However, she was able to exclude Garcia-Torres, Sierras father Steve LaMar and mothers former boyfriend Rick Gardner from the fifth sperm.

The defense interprets those findings as evidence that Garcia-Torres did not have contact with Sierra, including sexual contact, but that someone else did. They also reject the prosecutions theory that the sperm could have been transferred there through the wash, noting that the lab excluded her father and Gardner as contributors.

Boyd stuck to his washing-machine argument, but also alleged the sperm easily could have gotten on Sierras clothingfrom a sexual encounter that predated herdisappearance.

The defense and prosecution also strongly disagreed about how likely it is that Sierras DNA was on the cloth glove in Garcia-Torres trunk.

The lab concluded it was 340 trillion times more likely that the genetic material on the glove was a mixture of DNA from Sierra, Garcia-Torres and his former girlfriend than from an unknown person and Garcia-Torres and his girlfriend.

The likelihood ratio was calculatedbased on there being three contributors. But Barlow pointed out that a separate test Bell conducted on the glove indicated there could more contributors, which would reduce the likelihood, though it was not clear by how much.

Some of the six men and six women on the jury put their heads in their hands or stared blankly as Bell and the lawyers bandied about terms like alleles and stochastic thresholds. Loud sighs came from two jurors when the judge called the morning break.

However, near the end of the day, Judge Vanessa A. Zecher gave the jury an opportunity to submit written questions to Bell. Thethree jurors who took her up on her offer asked astute technical questions, suggesting that at least they understood the testimony.

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Sierra LaMar: With no body, DNA is star of the trial - The Mercury News