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Expert Admits Miscalculation on DNA Statistics

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TIMES STAFF WRITERS

Testifying Friday in the murder trial of O.J. Simpson, a leading statistician conceded that he had botched a set of calculations related to DNA tests in the case--an admission that had little direct bearing on the evidence but that defense attorneys used in an effort to undermine his credibility.

Bruce Weir, a nationally recognized professor of statistics at North Carolina State University, spent the morning filling in a few remaining details in the prosecution’s DNA evidence charts, in a session that jurors followed with mild interest.

But the panel snapped to attention as Weir, whose New Zealand accent and impressive academic credentials convey an air of authority, was challenged for mistaken calculations by defense lawyer Peter Neufeld. The attorney confronted Weir with his own charts, noting that Weir had calculated some DNA frequencies by assuming that a particular genetic marker was present while at the same time omitting that marker from other calculations.

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“If I did not include them, I am sincerely sorry,” said Weir after reviewing the material. “I am also embarrassed.”

Two of the jurors looked at each other with raised eyebrows when Weir said that. Virtually all the panelists seemed to take note, scribbling in their pads as Weir testified.

The DNA evidence forms the core of the prosecution case against Simpson, who has pleaded not guilty to the murders of Nicole Brown Simpson and Ronald Lyle Goldman. Although some other aspects of the prosecution case have been marred by slip-ups, the DNA evidence has unfolded smoothly for the most part.

In fact, Weir’s direct examination by the prosecution ended strongly, with the analyst vouching not only for his own results but for those produced by the two laboratories that performed the DNA analysis in the Simpson case.

As a result, Friday’s admission by Weir came as a surprise and was trumpeted by the defense, even though the statistics that it affects only involve a few of the less significant DNA samples in the case. Outside court, prosecutors acknowledged that when the figures are recalculated, they will be slightly less significant, but they downplayed the effects of Weir’s miscalculations.

“It’s going to have a minimal effect,” said Deputy Dist. Atty. Lisa Kahn, a leader of the prosecution’s DNA team.

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In the context of the overwhelming bulk of DNA evidence in the case, Weir’s miscalculation of a few results amounts to “no more than a speck of sand,” Kahn said, adding that the scientist’s willingness to acknowledge his error would only enhance his credibility with the jury.

Suggesting Bias

But Neufeld suggested that the figures in Weir’s reports might reflect more than errors, noting that in each of five tests in which the statistician failed to calculate the particular genetic marker, his erroneous findings tended to overstate the significance of evidence against Simpson.

“By failing to include the additional pairings . . . the numbers that are arrived at by you and put on that board are biased against Mr. Simpson, isn’t that correct?” Neufeld asked.

“As it turns out,” Weir said, “it looks that way, yes.”

Nevertheless, Weir angrily rejected the suggestion that he was tilting his results to favor the prosecution.

“When I do calculations, I do not consider any forensic implications,” he said, staring intently at Neufeld. “And if you are suggesting that I do, let me disabuse you of that right now.”

Despite Weir’s response and evident anger, Neufeld continued to hammer away at the theme, eliciting the statistician’s acknowledgment that he never consults with or testifies on behalf of defendants, only prosecutors. Weir had testified earlier that he did not work for defendants because he strongly believes in the forensic applications of DNA evidence, but Neufeld attempted to suggest that his beliefs amounted to bias.

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The confrontation between the defense attorney and the scientist was a charged one--the two men know each other professionally, but until Friday had never faced each other across a courtroom--and they sparred in front of the jury as well as outside its presence.

Before the jury was brought into the courtroom, Neufeld asked for copies of data underlying some of Weir’s charts. Weir, who said he had been up until midnight the night before working on the calculations, primly refused to work Saturday in order to comply with the defense request.

“I’m not going to work Saturday,” said Weir. “I’m quite tired.”

“As we all are,” added Ito. “We’re all glad it’s Friday.”

Another Lawyer Fined

During the cross-examination, tempers rose again, particularly when Neufeld attempted to question Weir about a letter that a group of scientists wrote to Nature magazine. Ito had previously warned the defense about using that letter, and when Neufeld touched on it Friday, prosecutors objected and the judge quickly intervened.

He summoned both sides to a sidebar conference, where the conversation began quietly but the voices quickly grew to a low rumble. A few jurors had been stretching, but they glanced over at the knot of attorneys as the tenor of the conversation seemed to escalate. Ito then suddenly halted the conference, striding back to his bench and audibly uttering the word sanctions as lead Simpson trial lawyer Johnnie L. Cochran Jr. fruitlessly gestured for him to return.

Outside court, Cochran confirmed that the judge had fined Neufeld $250 for raising the issue of the letter. According to Cochran, his colleague was furious about the sanction and had originally been unwilling to pay. After Cochran intervened, Ito agreed to lower the fine to $100 and Neufeld reluctantly agreed to pay, Cochran said.

That sanction marked the third this week: Cochran and Deputy Dist. Atty. Christopher A. Darden each were fined $100 on Wednesday after a heated debate over the prosecution’s attempts to recoup from its much-derided demonstration involving a pair of gloves--one found at the scene of the crimes, the other outside Simpson’s Brentwood home.

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Seeking to explain why those gloves did not appear to fit Simpson, prosecutors have blamed the demonstration on Simpson wearing latex gloves and on shrinkage by the crime scene gloves. On Wednesday, Darden also suggested that Simpson had stopped taking anti-inflammatory medication for his arthritis--a move that the prosecutor suggested could have caused the defendant’s hands to swell either for that demonstration or for one later in the week.

Arthritis doctors have expressed skepticism that laying off the medication would cause Simpson’s hands to swell overnight, and Friday, Cochran denied that Simpson ever stopped taking the medicine.

“There was a statement made by Mr. Darden at sidebar regarding Mr. Simpson not taking some medication, and that statement was false,” Cochran said. “Mr. Simpson has on every occasion taken his medication, and the medical records at the jail verify that fact.”

Resolving Issues

Although only half a day was devoted to testimony Friday, Ito used the afternoon to weigh a trio of issues that have dogged the trial for weeks, periodically surfacing inside and outside the courtroom.

The first harked back to a persistent theme in the case--the opposing sides’ complaints that their opponents are failing to turn over evidence in a timely manner. The latest complaint was brought by prosecutors, who said they still have received virtually no reports from defense expert witnesses.

Gerald Uelmen, one of Simpson’s attorneys, said most of the defense experts have not produced reports and are not obligated to do so. Although Ito said he had “expressed to defense counsel my skepticism,” he did not order the Simpson team to do anything more.

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At the same time, the judge partially granted a defense request to question three members of the district attorney’s staff--a law clerk who works for Darden and prosecutors Alan Yochelson and Terry White, the two lawyers who prosecuted the policemen in the state Rodney G. King beating case--about their questioning of LAPD Detective Mark Fuhrman.

Darden protested the defense effort to question those officials, saying the Simpson team was on an improper “fishing expedition” in order to determine whether Fuhrman admitted to prosecutors that he had uttered a racial epithet. Under oath, Fuhrman denied having used what the lawyers in the Simpson case have taken to calling the “N-word” at any time during the past 10 years.

Darden said he had no information suggesting that Fuhrman lied on the stand, implying that the detective did not contradict that statement when he was questioned as part of a practice session before he testified in the case.

But Uelmen, citing a report in Newsweek magazine suggesting that Fuhrman gave different answers during the practice session, said defense lawyers had a right to question the attorneys and clerk to determine what was said. Ito struck a compromise, asking the defense to submit questions to him and saying he would conduct the examination. Defense attorneys accepted that solution, but Darden said the prosecution may appeal.

As the court day ended, Ito granted a motion brought by ACLU attorney Douglas Mirell--joined by a variety of news organizations including The Times--seeking transcripts of hearings that have led to the dismissal of 10 jurors since the trial began. One excused juror, Francine Florio-Bunten, was in court for the session, and her attorney asked that transcripts of the hearings related to her be released. Simpson’s attorneys also favored release of the material, saying disclosure was warranted both because of their client’s 6th Amendment right to a public trial and the public’s 1st Amendment rights.

That left only prosecutors to object, and Ito seemed unimpressed with the arguments of Deputy Dist. Atty. Cheri Lewis, who tried to remind the judge that he had promised jurors anonymity when they were impaneled.

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“I’ve got jurors out there writing books about this--hardly a privacy interest worth protecting,” Ito told the prosecutor, interrupting her presentation.

The judge said he would review the transcripts, remove any potentially personal material and then release the file--which he said includes hundreds of pages and perhaps 30 volumes.

The documents will be made available early next month.

Times staff writer Andrea Ford contributed to this article.

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