REDWOOD CITY, Calif. >> As notorious convicted murderer Scott Peterson watched from a monitor in a state prison in Amador County, defense and prosecution lawyers battled in court Wednesday over whether he should be granted another chance to prove he didn’t kill his pregnant wife, Laci, and their unborn son two decades ago.

“The case cries out for further investigation,” Paula Mitchell, Peterson’s new defense lawyer from the Los Angeles Innocence Project, told the judge.

Dave Harris, a Stanislaus County deputy district attorney who helped prosecute Peterson in 2004, argued the opposite.

“The people know the truth,” Harris said. “They know he’s guilty of murdering his wife and unborn son.”

San Mateo County Superior Court Judge Elizabeth M. Hill broke for lunch before Harris finished his argument. It was unclear whether she would rule on the case by the end of the day.

Like the trial 20 years ago, national news media, including a crew from Dateline NBC, attended the hearing – a testament to the endless fascination with the case of the handsome Modesto fertilizer salesman accused of killing his substitute teacher wife and dumping her body in the San Francisco Bay, while he made plans for a future with his mistress from Fresno.

The L.A. Innocence Project, which recently took up Peterson’s case, is asking the judge to compel prosecutors to hand over old evidence for renewed DNA testing. They are hoping that a stain on a mattress found in a burning van a day after Laci’s Dec. 24, 2002 disappearance will prove to be her blood. If so, defense lawyers say that would confirm that she was alive when Peterson went fishing that morning and she was kidnapped and killed by others, perhaps the men connected to a robbery across the street from her home.

The defense lawyers also want to retest the DNA from a length of plastic string found tied “in a bow” around the neck of the son they planned to name Conner. The bodies of Laci and Conner washed up separately along the San Francisco Bay’s Richmond shoreline in April 2003, not far from where Peterson went fishing on Dec. 23 and declared his wife missing later that day.

A coroner who conducted the autopsy on the bodies back then testified during the original trial that Laci’s uterus, which had protected the child in her womb for four months, gave way during an April storm and the baby exited the top and floated away. Peterson’s lawyers suggested, like defense lawyers at the original trial, that the baby had been born sometime after Laci disappeared and the assailants killed the baby and threw mother and child into the bay to frame Peterson, whose alibi had been widely reported.

“This is an entirely circumstantial case in which no murder weapon was found, no time or date was established, no cause or manner of death was established,” Mitchell from the defense team argued. “DNA could have changed the outcome” of the trial, she said.

As he did in a 337-page brief, however, Harris again recounted what he called “overwhelming” evidence against Peterson, including that Peterson told his mistress he had “lost” his wife before she actually disappeared and he would be spending his first holidays without her.

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