The sonar equipment used by the Santa Clara County Sheriffs office this week to look for evidence related to missing teen in two South County reservoirs has been used in other missing persons cases, officials said.
Notable missing person cases where the sonar was used include Laci Peterson in Modesto, a retired California Highway Patrol officer in Stampede Reservoir in Truckee, a fisherman in Bethany Reservoir in Alameda County, a swimmer in Avocado Lake in Fresno County, and a cold case homicide in the city of Santa Clara, according to Sheriff's spokesman Sgt. Jose Cardoza. Two of those cases were successful in yielding information pertinent to the case.
The sonar used is a 900 kHz Marine Sonic side scan shaped like a torpedo that is towed under a dive team boat. Acoustic signals sent and received to the right and left of the torpedo create reflections and shadows on objects on the reservoir’s bottom.
Analysts then interpret the images to determine any significance to the case. The images assist divers to be able to search within about 25 to 50 feet of where an object is spotted.
For previous coverage of the Sierra LaMar case, refer to the Sierra LaMar Disappearance: Comprehensive Updates and Information page.
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