REDWOOD CITY - Satellite tracking devices police covertly placed on Scott Peterson’s vehicles experienced glitches on at least four occasions, one of which seemed to confound the prosecution expert called to testify about the technology’s reliability.
“This is the first time I’ve seen it,” said Peter Loomis, an engineer with Trimble Navigation.
His comments came as the defense tries to show that the global positioning system technology used to track at least three vehicles Peterson used is unreliable and should not be admitted evidence in his murder trial.
No California court has addressed whether the technology is reliable enough to allow as evidence in a criminal trial.
The 31-year-old Modesto has pleaded not guilty to charges he murdered his wife Laci, and unborn son, Conner, on or just before Christmas Eve 2002. Prosecutors are seeking the death penalty.
It is unclear what prosecutors intend to show from the tracking data, which according to defense documents occurred from Jan. 3, 2003 to April 22, 2003.
Information discussed in court indicate that Peterson was tracked to San Francisco Bay, where he said he went fishing the day his pregnant wife was reported missing and where the bodies were later found.
A police detective testified at Peterson’s preliminary hearing that officers followed Peterson to the bay at least three times. Tracking data discussed in court also shows Peterson went to Fresno, where his girlfriend at the time of his wife’s disappearance, Amber Frey, lived.
Detailed questioning by defense attorney Mark Geragos sometimes boiled down to semantic wrangling.
“He calls it an error, you can it a defect, I call it a behavior,” Loomis said at one point as Geragos tried to highlight disputes between Loomis and another GPS expert.
Much of the discussion focused around whether the antenna that sends a signal to a satellite network was properly positioned.
Prosecutors want to keep secret where the tracking devices were hidden on Peterson’s vehicles, arguing that could compromise future investigations.