Jury Told of Huge Odds Pointing to Simpson : Trial: Panel hears statistics about DNA matches. Defense questions methods used to derive the numbers.

Fewer than one person in 170 million has the genetic characteristics of a blood drop found near the bodies of Ronald Lyle Goldman and Nicole Brown Simpson, and O.J. Simpson is one of the people with that rare combination, a prosecution expert in Simpson’s murder trial testified Thursday.

Blood on a sock found in his bedroom, meanwhile, only could have come from about one person in 6.8 billion--and one who could have been the source is Simpson’s murdered ex-wife, said Robin Cotton, director of the Maryland-based Cellmark Diagnostics DNA laboratory.

Seeking to draw the jury’s attention to the astronomical nature of those statistics, Deputy Dist. Atty. George Clarke asked: “How many people are on Earth?”

“I don’t personally know,” Cotton responded with a slight smile. “But the figure I’ve been told is about 5 billion.”

Many jurors visibly recoiled at those numbers, which only represent the conservative end of the estimates predicting the significance of so-called DNA matches. The odds could be even higher against someone else having left the blood in question, Cotton testified.

Some of the jurors, normally an impassive lot, literally did double takes as they were presented with those statistics, which prosecutors say conclusively show that Simpson, a beloved football idol, is a brutal killer guilty of a double homicide. Simpson has pleaded not guilty, and he sat impassively through the DNA revelations Thursday. Near the end of the day, his attorneys began their challenge to the DNA evidence, in part by questioning the methods used to produce the statistics introduced in court.

In contrast to Simpson’s cool demeanor, other trial participants seemed tightly wound on the dramatic and long-anticipated day.

Near the end of the session, a prosecutor and defense lawyer tried to shout each other down in front of the jury, an outburst that caused Superior Court Judge Lance A. Ito to slam both hands down on his desk--unlike some judges, Ito does not wield a gavel--and then fine each of the lawyers $250. After motioning for the jury to leave, Ito made defense lawyer Peter Neufeld and Deputy Dist. Atty. George Clarke pay immediately.

The jury did not get to see the money change hands, but it was present to witness the unveiling of the DNA test results, most of which were introduced just before the noon break. First, jurors and Simpson were allowed to study some of the original X-rays of the DNA test results. Once they had completed those examinations, a process made comprehensible by the four-day DNA seminar that prosecutors have conducted in Ito’s court, the questioning of Cotton immediately turned to the statistics.

All the results presented Thursday figure as part of the prosecution’s case, but the tests of the crime-scene blood and the socks represent some of the government’s most powerful evidence against Simpson. Those two items bracket the prosecution’s so-called “trail of blood” with statistically powerful numbers. And they bolster the government’s contention that Simpson was at the scene of the crimes and tracked the victims’ blood back to his car and into his own bedroom, where the socks were discovered.

At the same time, the results presented Thursday dramatically raise the stakes for one aspect of the Simpson team’s response to the charges. The lawyers have accused police of orchestrating a conspiracy to frame their client.

Faced with DNA test results suggesting that Simpson was at the scene, the defense’s conspiracy theory assumes increasing significance as a way of explaining how the test results from Cellmark--as well as expected results from another DNA lab--could so powerfully point to Simpson as the culprit. Regarding the bloody sock matched to Nicole Simpson, the defense has accused police of intentionally placing that blood on the sock. If that weretrue, it would explain why it later was found to match Nicole Simpson’s.

The defense is not entirely dependent upon jurors accepting the conspiracy theory, however. Simpson’s lawyers simultaneously have accused police of sloppy evidence-collection techniques and have suggested that they could have so badly handled samples that they contaminated them and invalidated any later results.

After the morning’s bombshell disclosures, defense attorney Neufeld embarked on the task of attempting to chip away at the power of Cotton’s testimony. He started by posing a hypothetical question suggesting that police inadvertently mingled samples from the crime scene and from Simpson’s Rockingham estate, in the process tainting the crime-scene items of evidence.

But prosecutors objected to that question, maintaining that the lawyer’s hypothesis assumed unproven facts by suggesting tampering or contamination when no evidence has supported such an assumption. Ito agreed, and for more than an hour, Neufeld floundered, trying to pose questions over repeated objections.

Although Neufeld met with little success, he did elicit Cotton’s acknowledgment that it was scientifically possible for cross-contamination to occur. She made a point of not saying, however, that she believed that the facts in the Simpson case supported such a hypothesis.

Unveiling Results

The statistical significance of the DNA matches capped a stunning morning for the prosecution in the Simpson case, one dominated by a series of dramatic unveilings in which Clarke lifted off magnetic cards and revealed the results of all the DNA tests performed by Cotton’s laboratory.

The conclusions pointed to Simpson as the likely source of five drops found near the bodies of the victims and to Nicole Simpson as the probable source of blood found beneath her fingernails. In his opening statement to the jury nearly four months ago, lead Simpson trial lawyer Johnnie L. Cochran Jr. said that blood did not match the types of either victim or the defendant.

Based on that blood test, Cochran suggested that police had identified the wrong culprit and had failed to pursue another suspect in what he called their “rush to judgment” against Simpson.

But prosecutors responded by saying that the test that Cochran relied on to make that allegation was subject to misinterpretation, and they have struck back by presenting other evidence showing that Nicole Simpson was the likely source. On Thursday, Cotton said that between one in 2,500 and one in 26,000 people have the genetic makeup consistent with the blood beneath Nicole Simpson’s fingernails.

Nicole Simpson is one of the rare people whose blood it could be, Cotton added.

Clarke and Cotton moved smoothly through four days of testimony, building from a patient lecture on DNA science to a scathing indictment of the defendant. At every step, attention was paid to detail. Thursday, for instance, the evidence boards used to present the information to the jury referred to Nicole Simpson by her maiden name, Nicole Brown, emphasizing the distance between her and the defendant.

Legal experts praised Cotton and Clarke for the way they presented the DNA evidence, some of which still remains to be discussed by witnesses from a second laboratory, the California Department of Justice lab in Berkeley. Although there is more to come, prosecutors succeeded Thursday, observers said, in laying out the most important element of their case.

“This is the day we were waiting for,” said Myrna Raeder, a Southwestern University law professor. “For the prosecution, it finally came together Thursday. They presented a mountain of genetic evidence, and it’s very difficult for the defense to get around that mountain without going to theories of tampering or saying everything got contaminated in the LAPD lab. This is evidence linking the defendant to the crime in a spectacular way.”

As Clarke concluded his questioning just after the lunch break, he posed one final question to the witness.

“Dr. Cotton, as a result of the testing and the results you’ve described at your laboratory, are there any questions in your mind about the accuracy of the results reported by your laboratory in this case?” he asked.

“No,” she responded calmly and confidently. “There are not.”

“All right, thank you,” said Clarke, turning slightly toward the jury. “No further questions.”

Defense Struggles

With that, the challenge shifted back to Simpson’s legal team, spearheaded for this witness by Neufeld, a nationally renowned expert on the legal issues involving use of DNA in criminal cases.

Neufeld’s initial cross-examination, however, was confusing and unproductive, as he ran aground attempting to elicit testimony from Cotton about a National Research Council study on DNA. Neufeld sought to question Cotton about that report, but to do so, he was first obligated to show that she had in some way relied upon its findings in formulating her testimony.

Time and again, Neufeld attempted to pose a question that would elicit Cotton’s acknowledgment that she had relied on the report. Just as often, she said she had not, frustrating the defense lawyer, who consulted frequently with his colleagues. Heads together, with Simpson sometimes contributing his own thoughts, the attorneys muttered suggestions to one another.

A few feet away, prosecutors looked on with bemusement.

Finally allowed to proceed, Neufeld zeroed in on the central defense challenge to the physical evidence: the notion that dozens of blood samples were tainted, either accidentally or intentionally, while in the possession of the LAPD.

If such contamination occurred, Neufeld asked hypothetically, “you wouldn’t be able to detect that kind of cross-contamination if you used 15 or 20 (DNA tests), would you?” he asked.

“Of course not,” Cotton answered.

Later, Neufeld pressed that theme, asking Cotton whether she had any way of knowing how much DNA could have been transferred from one sample to another, either through evidence tampering or inadvertent contamination.

“Of course I don’t,” she responded.

But that defense victory was short-lived. When Neufeld tried to draw a crude chart to use in questioning the scientist, his cross-examination again was cut short. Prosecutor Clarke objected to Neufeld including a line on his chart that raised the question of tampering by police.

When Neufeld kept writing after Clarke raised his objection, Ito abruptly interrupted and sent the jury out of the room. Jurors filed out quickly, and the judge warned the defense lawyer that the use of the word “tampering” was argumentative.

“I will change the word ‘tampering’ to ‘deliberate contamination,’ ” Neufeld proposed. Although he insisted that was a serious suggestion, members of the audience and prosecution burst into laughter, and Ito shook his head in amazement.

“I admire your chutzpah,” Ito said. “You can have ‘contamination.’ ”

Rebuked, Neufeld retreated to the defense table, where he hastily drew up a new chart, its blocky letters in stark contrast to the sophisticated prosecution exhibits that the jury has spent the week studying.

Raising Doubts

As the end of the court day approached, Neufeld seemed to hit his stride, peppering Cotton with questions about criticisms of the population genetics techniques used to produce the astronomical numbers in DNA cases--the same ones that she cited in linking Simpson to the murders.

Neufeld belittled the notion that Cotton’s lab could produce such overwhelming statistics when they are based on comparatively small testing samples, as few as 100 to 250 DNA tests in one case. Those samples were provided by the Red Cross and were based exclusively on subjects tested in Detroit, Cotton said.

Several jurors seemed surprised by that testimony, snapping their heads back and furiously jotting notes as Cotton explained it. The scientist defended the sampling technique, but others said that topic represents a potential area for the Simpson team to exploit.

“Instead of having a wide foundation at the bottom and building up to a narrow point, it’s as if the pyramid were upside down, a tiny database building up to a huge top,” said Gigi Gordon, a Santa Monica defense lawyer. “What basis do we have to believe these people are a random cross-section of any community? I’m not disputing the validity of DNA, but I have questions about the sample.”

At a news conference after Thursday’s hearing, Deputy Dist. Atty. Lisa Kahn, a DNA expert with the Los Angeles County district attorney’s office, defended the sampling techniques, saying that they were commonly employed in DNA cases.

“They are validated techniques used for well over seven or eight years,” she said. “There’s nothing new or special about this case or these samples.”

Neufeld bored in on those types of questions, asking Cotton whether other scientists had expressed doubts about the procedures for deriving the statistical estimates. She responded that five or six scientists had expressed doubts, which prompted Neufeld to theatrically read off the names of 25 scientists, asking her each time whether she had heard of the person and implying that all of them had raised questions about the techniques.

Those questions, Neufeld said, were raised in a letter signed by the scientists and submitted to Nature magazine. Neufeld did not get the chance to question Cotton about the letter, however.

The examination was interrupted by Ito’s angry imposition of fines against the lawyers, and when testimony resumed, Cotton said she had not based her opinions on the views of those scientists. She did agree to read the letter overnight, however. She may face questions about it today.

Outside court, Neufeld said the letter had been signed by a wide array of prestigious scientists. “That’s what we want to get in front of the jury,” he said.

Times legal affairs writer Henry Weinstein contributed to this article.

* D.A. VISITS D.C.: Dist. Atty. Gil Garcetti turns heads in Washington. B1

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Estimating the Odds

Blood samples submitted in the O.J. Simpson trial were subjected to two types of DNA tests. RFLP is the conventional technique used for DNA profiling; PCR is a newer but less precise technique that works with smaller samples. The chart shows who was identified as the source of each sample, according to Cellmark lab director Robin Cotton, and the odds that the sample could have come from somebody other than the person named.

SAMPLE TEST USED CONSISTENT WITH ODDS Bundy walkway PCR O.J. Simpson 1 in 5,200 to (4 drops) 1 in 56,000 Bundy walkway RFLP O. J. Simpson 1 in 170 million to (1 drop) 1 in 1.2 billion Bundy shoe print PCR Nicole Brown Simpson 1 in 48 to and Ronald Goldman 1 in 610 Fingernail PCR Nicole Simpson 1 in 2,500 to clippings (3) 1 in 26,000 Rockingham PCR O.J. Simpson 1 in 40 to driveway (1 drop) 1 in 3,400 Rockingham RFLP O.J. Simpson 1 in 170 million foyer (1 drop) 1 in 1.2 billion Rockingham PCR Nicole Simpson 1 in 2,500 to sock (1 drop) 1 in 26,000 Rockingham RFLP Nicole Simpson 1 in 6.8 billion to sock (1 drop) 1 in 530 billion

Researched by THOMAS H. MAUGH II / Los Angeles Times