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Members of the Ceres High School criminal justice class got in line at 5 a.m. Thursday so they could get into Courtroom 2 to sit in on the hearing. From right are Brianne Cooney, Marissa Andreasen, Shawna Eavis and Stacy Schuber. BART AH YOU/THE BEE

Peterson defense attorney Mark Geragos grilled Constance L. Fisher, a DNA expert for the FBI, about testing techniques. LAURIE McADAM/THE BEE

Scott Peterson consulted notes during a portion of Thursday's DNA testimony at his preliminary hearing. LAURIE McADAM/THE BEE

Joe and Janey Peterson -- Scott Peterson's brother and sister-in-law -- leave the Stanislaus County Courthouse after Thursday's testimony. AL GOLUB/THE BEE

By JOHN COTÉ

and GARTH STAPLEY

Last Updated: October 31, 2003, 05:37:06 AM PST

A federal DNA expert concluded her testimony Thursday after a second grueling day on the stand as Scott Peterson's defense sought to show a disputed DNA technique is unreliable and should be excluded from court.

Stanislaus County Superior Court Judge Al Girolami is set to hear testimony Monday from a defense DNA expert before making a decision on the issue.

FBI expert Constance L. Fisher was the only witness to testify for the second straight day in Peterson's preliminary hearing on double-murder charges.

FBI lab technicians used mitochondrial DNA testing on a single hair found attached to pliers in Peterson's boat and determined it could not have been his, but may have been his wife's.

If the FBI findings hold up, the hair could be a key piece of evidence linking Laci Peterson to the boat that her husband said he took fishing to San Francisco Bay on Dec. 24, the day she was reported missing. He said she was missing when he arrived back at their Modesto home.

Laci Peterson, 27, was almost eight months pregnant at the time. Scott Peterson, 31, is charged with murdering his wife and their unborn son, Conner. Prosecutors are seeking the death penalty.

Laci Peterson's body and that of her son were found in April along the bay's eastern shore, several miles from where her husband said he went fishing.

Defense attorney Mark Geragos spent much of Thursday questioning Fisher in an attempt to show that mitochon- drial DNA was a scientifically disputed technique. Geragos also tried to show that faulty equipment colored the FBI's results.

Fisher, who rolled her eyes at a question just 16 minutes into the morning session, held her ground under repeated questioning, saying the technique is widely regarded as accurate and scientifically valid.

"There is always debate going on in a community," Fisher said. But, she said, disputes about mitochondrial DNA are not "sizable."

Fisher acknowledged the FBI lab equipment could be "persnickety," but said routine problems did not compromise test results.

Mitochondrial DNA differs from nuclear DNA, which is found in the nucleus of a cell and positively identifies tissues. Mitochondrial DNA is found elsewhere in a cell and cannot be used as a unique identifier.

A maternal tie

Mitochondrial DNA is passed down from one's mother, and all maternal family members share the same mitochondrial DNA in most cases, Fisher said.

Mitochondrial DNA analysis can rule out a match with a known sample, but cannot show that a test sample came from a specific person.

Fisher testified that the hair found in Peterson's boat could have come from Laci Peterson's mother or brother. Laci Peterson's half sister, Amy Rocha, has a different mother.

Geragos attempted to show that the FBI failed to follow its own guidelines, asking Fisher why the FBI lab did not extract DNA from one of Peterson's bones and compare it with the hair.

Fisher said that was not necessary because analysts had a viable saliva sample from Peterson's mother, Sharon Rocha, and that analyzing DNA from a bone is more difficult than from a saliva sample.

FBI guidelines Geragos read in court said technicians "should" compare results with a second tissue sample.

"'Should' has wiggle room in it," Fisher said. "There is a difference between 'should' and 'must.'"

Geragos also took aim at the computer

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<<<<<<<<<>>>>>Hergus:
Here is anther pic of Joe Peterson to add to your files of family images

Peterson lawyer chips at DNA flaws

Posted on Fri, Oct. 31, 2003

Peterson lawyer chips at DNA flaws

By Brian Anderson

CONTRA COSTA TIMES

MODESTO - Attorney Mark Geragos continued on Thursday to pound on forensics testing that linked a hair found in Scott Peterson's boat to his dead wife, saying that the FBI's DNA handling procedures are incredibly flawed.

In a second day of cross examining FBI biochemist Constance L. Fisher, Geragos zeroed in on the agency's reliance on what he characterized as an unreliable, "evolving" practice.

Fisher acknowledged that a database housing thousands of mitochondrial DNA patterns could be more comprehensive and that a known technological limitation of the system's computer software was never fixed.

She also said during occasionally charged questioning that more accurate nuclear DNA tests of bone were avoided in favor of using "faster, easier" -- but less exacting -- mitochondrial DNA exams. Laci Peterson's mother provided a saliva sample used to link the strand of hair to Laci.

"We know from our experience that bone is very difficult to work with," Fisher said, adding that testing bones "would have given us the same information."

The hair, potentially a key piece of evidence for prosecutors, was pulled from a pair of pliers investigators discovered in Scott Peterson's 14-foot aluminum boat. Peterson had told authorities he was fishing the waters of San Francisco Bay on Dec. 24 when Laci Peterson, 27, his wife of five years, vanished from the couple's quiet Modesto neighborhood.

Her decomposed body and that of the couple's unborn son washed ashore in April in and near Richmond. Peterson, 31, was arrested days later and charged with their slayings.

Prosecutors are trying to convince ------------

Peterson's friends describe his letters written from cell

By GARTH STAPLEY
BEE STAFF WRITER

Last Updated: October 31, 2003, 05:37:06 AM PST

A heavy metal door clangs shut in the three-story Stanislaus County Jail. Scott Peterson buries his head in a blanket, afraid to let other inmates see him crying. So goes life behind bars for one of the country's most notorious suspected killers, according to letters that Peterson sends various acquaintances, his dead wife's friend said Thursday.

"He makes references to memories of Laci," said Heather Richardson of Ventura County. She said she compared Peterson's letters to others that he apparently sent to friends in Stanislaus and Monterey counties -- and found nearly identical passages.

"It's a little irritating to us," said Richardson, who was maid of honor at Scott and Laci Peterson's 1997 wedding. Her husband, Mike, was best man. Scott Peterson took refuge from the media at the Richardsons' home in January as searchers looked for his missing wife.

"We were their best friends," Heather Richardson said, "and (Scott) doesn't have unique thoughts for us. He writes generally the same stuff to everybody."

A source said Peterson, a member of one of the Rotary Clubs in Modesto, wrote at least a half-dozen letters to "community leaders" about a week after his arrest April 18. All contained similar wording expressing desire to continue friendships after his "exoneration," the source said.

Peterson avoids writing in detail about the double-murder case against him, Richardson said.

"He never says, 'I didn't do this,' but it's inconceivable in his mind that he had anything to do with it," Richardson said Thursday.

"It's kind of cryptic, as far as I'm concerned," she continued. "It's not exactly what you'd expect from someone facing what he is. It's like he is not realizing the reality of the situation he's in."

Peterson faces the death pen- alty if convicted of murdering his wife and their son, Conner.

A long-awaited preliminary hearing got under way Wednesday and is expected to continue through most of next week.

"In an upcoming forum, you will be able to see the evidence my team has put together," Peterson once wrote, Richardson said. She said she assumed he referred to the preliminary hearing.

A branch of the Simi Valley fire this week burned to the Richardsons' property in Fillmore, she said, but did not reach the house.

"Good or bad, it's nice to be preoccupied down here so (the hearing) is not always everything I think about," Richardson said. "At this point, we're just waiting to hear all the evidence."................