State Justices Uphold DNA Evidence, With Limits

In its first such ruling on DNA evidence, the California Supreme Court upheld the admissibility of DNA test results Monday but said prosecutors will have to show that correct scientific procedures were followed on a case-by-case basis.

Although DNA evidence has been used in many California cases, prosecutors had to go through extensive hearings to prove DNA testing was generally accepted scientific technology, and some state appellate courts had expressed reservations about it.

The Supreme Court’s unanimous ruling was complex, giving advantages to prosecutors and defense attorneys. It settled conflicting holdings by lower courts by ending debate over the scientific acceptability of certain methods. In many cases, courts will now have to hold only limited hearings on whether correct procedures were followed.

The court approved the use of a DNA test known as RFLP, which can with a high degree of certainty show a match with only a speck of blood or other specimen. The court also embraced a conservative approach for calculating the statistical odds of a false match, a process that gives the benefit of the doubt to the suspect.

But prosecutors who want to assert that DNA can identify suspects with near-fingerprint accuracy will be restrained by the court decision. In those cases, full-blown hearings must be held to decide whether the methodology for making such dramatic claims has won general acceptance by the scientific community.

Deputy Atty. Gen. Jo Graves said the decision was a mixed bag for prosecutors. “Right now this limits us to the more conservative calculations,” she said.

The court’s ruling overturned the rape conviction of Sergio Venegas, who was tied to a 1989 sexual attack in a Bakersfield motel largely by DNA analysis of his semen. In Venegas’ case, the court said the statistical probability of a false match was improperly calculated.

The law-and-order Criminal Justice Legal Foundation nevertheless praised the decision for clearing the way for DNA evidence in trials throughout California. “The decision prevents future court challenges on this type of evidence,” the group said.

But University of Santa Clara law professor Gerald Uelmen said the decision also will be “extremely helpful to the defense” in criminal cases.

“What this opinion says is there are still a lot of unresolved questions about DNA, and those questions will be rigorously examined by appellate courts,” said Uelmen, who was one of the defense lawyers in O.J. Simpson’s criminal trial. “It is great news.”

He said the rigor of the analysis in the ruling also shows that the Supreme Court “is not going to gloss over these questions” in future cases.

Deputy State Public Defender Valerie Hriciga said the ruling “really reaffirmed the trial court’s power to act as a gatekeeper and keep out the result of genetic tests when generally accepted scientific procedures were not followed.”

In a ruling written by Justice Marvin Baxter, the Supreme Court held that a 1992 National Research Council procedure for calculating the likelihood of a random match is generally accepted by scientists, and hearings on its admissibility are not necessary.

In explaining his reasoning, Baxter said the method erred on the side of the defendant and he noted that none of the critics contended that it would lead to conviction of the innocent. The court may still approve a less conservative method in a pending case.

“Virtually all of the scientists who have criticized [the 1992 recommendations] do so on the basis that those statistical methodologies produce figures that are far too conservative and unduly favorable to the suspect,” Baxter wrote.

But trial courts must still determine whether the calculations “in the particular case followed correct scientific procedures,” Baxter wrote.

In Venegas’ trial, an FBI criminologist testified that the genetic profile of evidence found at the crime scene was shared by only one in 65,000 people or one in 31,000 among southwestern Hispanics.

The Supreme Court upheld the basic RFLP methodology the FBI used to match semen at the crime scene to Venegas. But the court said Venegas is entitled to a new trial because the FBI failed to follow correct scientific procedures in calculating the statistical probability of a random match.

Baxter noted that the prosecution has admitted that without the DNA evidence, “there was insufficient evidence to convict” Venegas. “It was reasonably probable [that the] defendant would have had a more favorable verdict had the trial court not erroneously admitted DNA evidence,” Baxter wrote.

Deputy Atty. Gen. Graves expressed confidence that Venegas would be found guilty in a retrial because conservative statistical methods will still show that he was the rapist.