Authorities have spent days combing the land to see if Dugard's alleged captors can be tied to two other abductions from the late 1980s, but they also have cautioned that it's still too soon to know whether a soil "anomaly" and found bone fragments could mean any previous digging on the property was crime-related.
"It could be significant, and it could not be significant, but it's helping us target where we might do some digging," said Hayward Police Lt. Chris Orrey.
Hayward and Dublin police are investigating to see if there are any possible links between Phillip Garrido and the unsolved 1988 abduction of 9-year-old Michaela Garecht and the 1989 disappearance of 13-year-old Ilene Misheloff.
"This neighborhood has now become accustomed to police investigators and news crews," observes CBS News Correspondent John Blackstone. "After all the attention of recent weeks, it seems all the more surprising that, for years, neighbors seemed to barely know what was happening" at the Garrido house.
More on the Jaycee Dugard investigation on CBSNews.com
Body Buried in Garrido Yard?
More Bone Fragments Found at Garrido House
Girls Other Than Jaycee in Garrido Yard?
Sources: Inmates Threatening Nancy Garrido
Dr. Phil: Dugard, Kids Face Long Road
Jaycee's Terror as Her Ordeal Began
Garrido and his wife, Nancy, have been charged in the 1991 kidnapping of Dugard, who was reunited with her family last month after authorities arrested the couple. Prosecutors say the Garridos hid Dugard in their Antioch backyard. They have pleaded not guilty.
While Hayward and Dublin authorities have not directly interviewed Dugard, who was abducted outside her South Lake Tahoe home in 1991, they have asked other law enforcement agencies involved in the case to ask questions for them, Orrey said.
Dugard has not supplied information to indicate the Garridos were involved in the kidnappings of Garecht or Misheloff.
For four straight days, authorities have searched the Garrido's land and a neighbor's yard for clues. They expect to resume their search Monday.
Investigators already have dismantled the hidden encampment of sheds and tents where authorities say Dugard was held and lived with the two daughters she had by Garrido. They also removed 19 truckloads of debris from the yard and looked inside the Garridos' house.
Orrey said boxes of papers in Phillip Garrido's handwriting have been removed from the house.
Bill Silva, a professional archaeologist who has led excavations for ancient skeletal remains and historical artifacts in California, spent Thursday and Friday pushing a ground-penetrating radar in a grid pattern around the Garrido property.
On Friday, he picked up signs of disturbed soil that could indicate a pit where previous digging has occurred. Two cadaver dogs picked up a scent that may be a sign of remains in the same area on Thursday.
Orrey says the next step is to bring in two sets of dogs - one trained to sniff out decomposing bodies and the other trained to detect older bones.
"We have set it up just like an archaeological site, where we are looking for real ephemeral remains," Silva said of the backyard dig in Antioch. "This is the first crime scene I've worked on, unless you consider a Native American massacre site."
If there was previous digging on the property, it could be due to something as simple as the fact that the neighborhood used to be made up of citrus orchards and walnut groves, he said.