GPS data at issue in Peterson case
Judge to hear defense request to sequester jury
Scott Peterson is charged with killing his pregnant wife, Laci, and their unborn son.
Scott Peterson's attorney wants tracking evidence suppressed.
REDWOOD CITY, California (CNN) -- Prosecutors and defense attorneys in Scott Peterson's murder trial are due in court again Tuesday to argue whether information gathered from tracking Peterson's vehicles by satellite after his wife disappeared should be admitted as evidence.
Peterson, 31, is charged with killing his pregnant wife, Laci, and their unborn son. Their bodies washed up separately on the shore of San Francisco Bay in April 2003.
After Laci Peterson vanished in late December 2002, police in the couple's hometown of Modesto placed global positioning system devices on three vehicles used by Scott Peterson to track his whereabouts. GPS devices use satellite technology to pinpoint locations.
A prosecution witness testified last week that the GPS devices, despite briefly malfunctioning at least four times, accurately tracked Peterson to San Francisco Bay.
Peterson told police he was fishing in the bay December 24, 2002, the day his 27-year-old wife disappeared, and had launched his boat from the Berkeley Marina. The bodies washed ashore a few miles from the marina.
Prosecutors said the GPS evidence is circumstantial but indicates that Peterson behaved as if he were guilty by driving to San Francisco Bay in January 2003, as if afraid someone would find the bodies.
Scheduled to testify Tuesday is another prosecution GPS expert, and a defense expert who is expected to challenge the accuracy of the devices.
Mark Geragos, Peterson's defense attorney, argued last week that the tracking system malfunctioned and that the technology is not legitimate science.
The issue is whether GPS technology is reliable enough to be used in California courts.
Judge Alfred Delucchi could rule on the admissibility of the GPS data Tuesday and has said he would address Geragos' request to sequester the jury this week.
Geragos claims extensive media coverage has hurt Peterson's chances of a getting a fair trial and that jurors should not be further exposed to it once they are selected.
Geragos successfully argued to relocate the trial from Stanislaus County to San Mateo County last month because of pretrial publicity. (Full story) He asked to sequester the jury for the four- to six-month trial, claiming the new venue is more hostile than Modesto.
In addition, Geragos wants a separate jury to determine the penalty if Peterson is convicted, contending people who qualify for death penalty cases often favor the prosecution. Prosecutors have said they would seek the death penalty if Peterson is convicted.
The high-profile attorney also wants the court to exclude statements Peterson made to the media after his wife disappeared.
Geragos cited billboards along the highway near the court as examples of how ubiquitous the coverage is. The billboards depict Peterson in an orange jumpsuit after his arrest and ask, "Man or Monster?"
Then there's the made-for-television movie about the case, "The Perfect Husband: The Laci Peterson Story," that was broadcast last week on the USA Network. (Full story)
Laci Peterson's family expressed their fears about the movie to reporters last week.
"Our concern is everybody is a potential jurist, and it could inflame a potential juror," stepfather Ron Grantski said.
No date has been set for the start of jury selection.
CNN's Rusty Dornin contributed to this report.