Sandra’s body was found in an irrigation pond a couple of miles from her home.
 
Police are concentrating the investigation on the mobile home park where the girl lived with her family.
 
Ernie Allen of the National Center for Missing and Exploited Children says in similar cases the culprit is familiar with the victim.
 
Allen: "It is most likely that this is not a random stranger, but is somebody who had access to Sandra, at least casually. Knew her, saw her, was around her."
 
Police have served a search warrant on at least one residence in the mobile home park.
 
They have also cordoned off a Tracy Church with yellow crime scene tape.
 
No one has been arrested in connection with the case.