Thursday's air and ground search yielded no clues as to Danielle's whereabouts, according to the San Diego police press office. The press office did not release details regarding what led police back to the Valley on Friday to conduct an air search.
David Cohen, a spokesman for the San Diego police, said the helicopter trip over the desert Friday "did not produce anything new."
There was no information on whether police would return to the Valley. Carter said he did not think San Diego investigators were in the Valley on Saturday.
He added his department is ready to provide assistance to San Diego police if called upon to do so again.
"Our people, our volunteers will be out there helping if they need us," Carter said.
Cohen said detectives would continue to follow leads and conduct interviews throughout San Diego County over the weekend.
The search for Danielle turned to the Valley as police continue to look at a neighbor of Danielle's family, David Westerfield, 49, as a "possible suspect."
Westerfield, according to reports, was in Imperial County last weekend with a motor home. Westerfield voluntarily led investigators to the Valley and showed them where in the Valley he said he had been. One of those places was the Glamis area.
That is where investigators focused their search Thursday, along with areas in the west desert.
Westerfield has not been arrested and remains only a "possible suspect" as police follow some 200 leads.
In the Imperial Valley, the De Anza Search and Rescue squad — a volunteer unit of the Sheriff's Office — took part in the search Thursday.
Ed Goodell, a squad member, said Saturday that 10 volunteers from the squad took part in the search.
He said investigators did "line" searches in the Glamis area and in the western desert near the Ocotillo area. A line search is where searchers line up spaced out over an area and walk the area. Goodell added De Anza volunteers joined in the line search.
Units searched from about 8 a.m. to 4:30 p.m., Goodell said, adding about half the day was spent in Glamis, the other half in the county's west desert.
Goodell said to his knowledge nothing was found.
Still, he said in search and rescue missions the primary thing can be not what you find but what you do not find "because that eliminates an area."
Goodell added of the search, "It's a needle-in-the-haystack thing unless they get something really concrete. You have to keep picking away at it."
Goodell, like Carter, said he had no information on whether San Diego investigators will return to the Imperial Valley desert.
>> Staff Writer Darren Simon can be reached at 337-4082.