The use of DNA evidence in criminal cases was given another boost by the California Supreme Court on Monday when it upheld an attempted-rape conviction that relied heavily on a DNA match.
Ruling in the case of Frank Lee Soto, a Westminster gardener convicted of the attempted rape of an elderly widow in 1989, the court found that the method used to calculate the probability of a DNA match was scientifically acceptable.
Prosecutors hailed the decision, saying it will make it easier for them to present strong statistical evidence that will have an impact on juries.
"It's a very significant ruling," said state Deputy Atty. Gen. Frederick R. Millar Jr., who argued the case before the high court. "We've been waiting for some time to get this issue resolved. . . . [It] has been up in the air in California."
Soto's attorney said he was not surprised by the decision, which included a lengthy, complicated discussion of DNA techniques.
"When you looked at other states, they're all coming down on the side of letting this evidence" into cases, said attorney Richard Schwartzberg of Santa Ana.
The defense lawyer had argued that the statistical methods used by the prosecution were under dispute in the scientific community and therefore should not have been presented at trial.
Schwartzberg said Soto's chances on appeal had suffered because scientific thinking on DNA evidence had evolved as the case plodded through the courts.
"I think Soto would have won if it had not been delayed the way it was," he said.
Soto, who served three years in prison for the crime and completed parole, continues to maintain his innocence, Schwartzberg said. "It's going to put his name back in the news and drag him through the case again," the attorney added.
In another case last year, the state Supreme Court upheld the general admissibility of DNA test results, which are playing a growing role in criminal cases around the nation--not only to gain convictions, but also to clear people who have spent years in prison on rape or murder charges.
Monday's ruling goes a step further than last year's decision, upholding a statistical method--known as the unmodified product rule--used to calculate the probability of a chance match between a suspect's DNA and a piece of evidence found at a crime scene.
"At present it is clear from the evidence presented in this case, the published scientific commentary, and the clear weight of nationwide judicial authority that use of the unmodified product rule in DNA forensic analysis has gained general acceptance in the relevant scientific community," stated the unanimous decision.
In Soto's case, the prosecution presented evidence that the DNA from the defendant's blood sample matched that of semen stains found on the bedspread of the 78-year-old woman he was accused of raping at knifepoint.
A criminalist testified that the chance of a random match between the two samples was 1 in 189 million.
The DNA evidence figured heavily in the case because the attacker's face was covered with a stocking mask and the victim was unable to testify because of a stroke she suffered before the trial.
A jury acquitted Soto of forcible rape and a weapons charge but found him guilty of attempted rape.