Simpson Case Heightens Stakes in ‘DNA War’ : Courts: Defense will argue merits of testing results either way. It is one of the most vitriolic debates in law, medicine.

As scientists perform the tests that could alter the course of the O.J. Simpson murder case, the former football star’s attorneys are constructing two parallel defense strategies--one for whatever results the DNA analysis produces.

If the tests show that Simpson’s blood does not match that of samples found at the scene of the crime, two of the nation’s foremost criminalists, Dr. Henry Lee and Dr. Michael Baden, will be prepared to argue that someone other than Simpson is almost certainly the killer.

But if the tests indicate that Simpson’s DNA matches that of samples recovered by detectives, his lawyers are ready for that too. They have hired Barry Scheck and Peter Neufeld, two of the nation’s premier legal experts on the shortcomings of DNA evidence and the limits of its usefulness in identifying criminal suspects.

“We have a good team assembled that can deal with any set of results,” said Johnnie L. Cochran Jr., one of the leading members of Simpson’s defense team. “We can cover it both ways.”

No matter which DNA faction of Simpson’s team gets the call, the experts and lawyers who square off to argue DNA will be wading into one of the most vitriolic debates in the legal and medical communities today. It is a highly technical area where biology and statistics converge, and it has pitted the operators of forensic labs against academic scientists in a furious disagreement over how DNA tests are performed and whether they are reliable enough to send defendants to prison in certain cases.

The raging debate over DNA is complicated further by shifting legal standards for considering scientific evidence in court. In 1993, the U.S. Supreme Court adopted new rules for judges to employ in admitting scientific evidence, but those rules only apply in the federal courts. Legal experts are eagerly awaiting word on the subject from the California Supreme Court, whose rulings bind state judges such as the one presiding over the Simpson case.

All of that could give Superior Court Judge Lance A. Ito a huge problem to sort out. Since he was assigned to the case last month, Ito has broached the DNA issue once and will return to it Tuesday when he is expected to hear arguments about splitting blood samples.

As the case goes forward, he could have bigger dilemmas before him. Experts say it could take weeks for Ito to hear conflicting testimony about the DNA, then to decide whether the tests are admissible and, finally, to determine how much statistical significance jurors should attach to any possible DNA “match.”

All those decisions could have important consequences for the case, and Ito will have few hard-and-fast rules to guide him.

“Nothing is nailed down here,” said John Wiley, a UCLA law professor and former federal prosecutor. “Judge Ito really has got a nightmare on his hands.”

The forum in the explosive Simpson case will be what is known as a “Frye hearing,” a dry, technical and possibly prolonged session that will focus on contested evidence in the case and which Ito has indicated he intends to conduct after a jury is impaneled.

Neither side in the DNA war disputes the central scientific premise behind the process--that different people have different DNA structures, and that DNA testing can therefore identify or exclude people as the sources of blood, hair or tissue samples.

Even a skeptic such as Scheck has said that DNA testing is “an extraordinarily powerful tool that is going to be done reliably.” But, he added: “Has it yet become reliable? No.”

Egged on by rival lawyers, scientists have staged an increasingly testy disagreement on that subject, accusing colleagues of faking results, stealing others’ work and slanting experiments for money. The debate has grown so heated that one expert titled his article on the subject “Lessons From the DNA War” and lists among his credentials the fact that one of his articles has been reprinted three times and plagiarized once.

Some scientists say they have been threatened with income tax audits or investigations into their immigration status after testifying in DNA cases. Others who have been through the experience describe it as “harrowing” and have vowed never to take the stand again.

“These cases have forced the adversarial process into the scientific process,” said Deborah Williamson, an assistant federal public defender from Phoenix who has waged an aggressive challenge to DNA evidence on behalf of a client. “Scientists are not used to being challenged and picked at. It’s gotten pretty mean.”

Few expect the Simpson case to prove an exception. No eyewitnesses to the murders of Nicole Brown Simpson and Ronald Lyle Goldman have come forward, and Simpson has vigorously maintained his innocence, saying through his attorneys that he was at home at the time of the killings. So DNA evidence is likely to form an important element of the prosecution’s effort to show that Simpson was at the scene of the crime.

Preliminary DNA tests conducted by the Los Angeles Police Department lab in June showed that Simpson could have left blood droplets leading away from the murder scene, and that blood found on a glove outside his Brentwood mansion could have come from the two victims.

Those tests were not presented during last month’s preliminary hearing. Prosecutors instead relied on results of conventional blood testing done on a droplet discovered at the murder scene--results that a police expert testified pointed to Simpson as a likely source of the drop. Since the hearing, prosecutors have sent their blood samples to a Maryland laboratory, Cellmark Diagnostics, where scientists are performing more rigorous DNA tests known as restriction fragment length polymorphism (RFLP) analysis.

That procedure is the most commonly accepted by courts, but it too has come under assault in numerous trials. Leading the attack often is the tag team of Scheck and Neufeld, a highly regarded pair of attorneys who pioneered the defense bar’s challenges to DNA in the late 1980s.

“If I was the defense, there isn’t anybody else I would call,” said Myrna Raeder, a professor at Southwestern University School of Law. “Barry is incredibly well-respected. . . . In the mid-1980s, nobody was challenging DNA at all. Then Barry took a look at it and started talking to scientists. He almost single-handedly, with Peter Neufeld, started this debate.”

Among the earliest milestone cases in the DNA war was one known as People vs. Castro. On Feb. 5, 1987, a 20-year-old pregnant New York woman and her 2-year-old daughter were found stabbed to death in the Bronx. A janitor named Joseph Castro was charged with the murders, and prosecutors offered as evidence a bloodstain from his watch.

That stain, according to DNA experts, matched the blood of the dead mother. They concluded that the chances of it having come from anyone else were more than 189-million-to-1.

The lab in that case was New York-based Lifecodes, and its findings were backed by a number of prominent scientists. But Scheck and Neufeld fought back vigorously, suggesting that the lab’s procedures were sloppy and that analysts had ignored data that might tend to clear the defendant. Some experts who originally testified for Lifecodes eventually reconsidered and joined in the criticism.

After an exhaustive Frye hearing, the judge ruled that the evidence of the victim’s blood on Castro’s watch could not be admitted.

But the Castro case, which might have been an unmitigated victory for critics of DNA testing, ended on an eerie note. Having successfully fought to keep the DNA evidence out of court, Castro then pleaded guilty to the crime.

Since that case, Frye hearings have become the increasingly fractious testing grounds over the admissibility of DNA evidence and the reliability of the principal DNA laboratories, Lifecodes and Cellmark.

Both laboratories have steadfastly defended their work and noted that results of their tests have been accepted in courts nationwide.

Acceptance has not come without a fight, though. In case after case, Scheck and Neufeld have attacked both labs for sloppy work--Neufeld once accused Lifecodes of producing “garbage”--and have questioned the statistical significance of DNA “matches.”

To arrive at the odds of two “matching” samples coming from different sources, analysts perform a simple arithmetic exercise. Say there are three characteristics in a given DNA sample and each one occurs in the general population with a frequency of 1 in every 10 people. By multiplying the odds of a person having each characteristic, analysts might conclude that there was a 1-in-1,000 chance of a single person having all three characteristics. (Multiplying .10 x .10 x .10 produces a result of .001 or 1 in 1,000.)

Proponents of DNA testing say presenting the jury with those statistics helps allow jurors to assess the likelihood of samples coming from the same or different people. But critics say there is a hitch: Imagine that the three characteristics being studied reflect the coding for black hair, dark eyes and dark skin. And imagine that sample came from an Indian reservation in Arizona or New Mexico. The sample could be linked to far more people in that population than the 1-in-1,000 ratio would indicate.

To avoid that, analysts study segments of DNA that are believed to be highly individual, avoiding sections that code for hair or eye color, for instance. Nevertheless, critics say the statistical significance of a DNA match can vary by region, by the specific characteristics being studied and by the population from which the sample is drawn.

All those factors complicate any statistical conclusions about the sample’s significance, even if a “match” is produced.

Assuming Cellmark’s tests withstand any quality control challenges from the defense, most legal experts believe that Ito will allow jurors to hear DNA evidence in the Simpson case. But Peter Arenella, a UCLA law professor, echoed the view of other experts in predicting that Ito probably will force prosecutors to use conservative estimates when it comes to assessing the probability that any DNA sample can be matched to Simpson or the victims.

That could narrow the field of possible suspects but also leave the Simpson defense team with room to maneuver. At the preliminary hearing, a police expert said conventional blood tests demonstrated that a blood drop found at the crime scene could only have come from about one in every 200 people--including Simpson.

Gerald F. Uelmen, one of Simpson’s lawyers, pounced on that statistic to note that tens of thousands of people in the Los Angeles area thus could have left the drop.

In the end, moreover, even if the DNA evidence shows everything that prosecutors hope it will, their case would still be incomplete.

The onetime football superstar is charged with two counts of first-degree murder, a charge that requires prosecutors to prove premeditation.

Doing that will require prosecutors to produce old-fashioned evidence such as testimony about a defendant’s statements to police, behavior before and after the crimes and relationship to the victims. Assessing Simpson’s premeditation forces jurors to venture inside the Hall of Famer’s head. And there, even DNA cannot lead them.

“At the most, DNA can link you to a killing,” said Harland W. Braun, a noted criminal defense lawyer in Los Angeles. “It doesn’t do anything beyond that. To get to premeditation or intent, the prosecution is going to have to do more, and it’s going to have to rely on other kinds of evidence.”

* THE LAB INVOLVED: Cellmark Diagnostics prepares for the battle ahead. A28