SAN DIEGO -- Authorities took a highly trained tracking dog through the home of missing Sabre Springs second-grader Danielle van Dam Tuesday in hopes of turning up clues that will clear up the mystery of her disappearance.

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Officers led the bloodhound, which was on loan from the Riverside County Sheriff's Department, from room to room in the van Dams' northern San Diego house and through their yard late in the afternoon.

"We're going to try to pick up a scent," Lt. Jim Duncan told reporters. "This dog is different than the dogs we used the other day, and it's supposed to be a maybe a little bit better-trained."

Investigators said they were unsatisfied with a canine search of the two-story Mountain Pass Road home they conducted within the first few days of the 7-year-old's presumed kidnapping.

"The FBI has utilized this particular dog in the past, and they felt very confident in its abilities," Duncan said.

Officials would not say if the brown-and-black, floppy-eared hound seemed to have detected anything of value.

Danielle's disappearance 11 days ago has generated intensive searching, heavy national news coverage and various rewards totaling $85,000.

When they filed a missing-person report the morning of Feb. 2, Brenda and Damon van Dam told authorities that the last they'd seen of their daughter was when the father put her to bed after 10 o'clock the night before.

Since then, various law enforcement agencies and teams of citizen volunteers have searched the upper-middle class neighborhood and its environs, as well as large sections of the Imperial County desert.

The sun-baked region near Arizona became a focus of the investigation when authorities learned that a man who lives two doors away from the van Dams traveled there around the time the girl vanished.

The neighbor, 50-year-old David A. Westerfield, apparently took his recreational vehicle to a spot near Glamis over the weekend of Feb. 2-3.

Calling the design engineer and off-roading enthusiast a "potential suspect" in Danielle's disappearance, detectives have twice gone through his house with service dogs.

During those searches, officers carted off boxes and bags full of household items. In addition, police impounded Westerfield's sport utility vehicle and the motor home he took to the desert over the weekend.

Westerfield has hired criminal defense attorney Steven Feldman to represent him in the case, even though he has not been charged with any offense.

No arrest in the case is imminent, Duncan said.

Tuesdy afternoon, Duncan said investigators will do "whatever it takes" to find Danielle.

"This is the highest priority they have, and they're working on it night and day," Duncan said during an impromptu briefing outside the van Dams' home.

Hoping to hasten efforts to find Danielle, her parents Monday announced a $25,000 reward for information leading to the safe return of their daughter.

Standing outside their upscale home in the clear, warm morning air, the couple displayed a large poster bearing a photograph of their daughter and touting their cash incentive for tips in the case.

"I hope this will motivate someone who knows where she is to step forward, return her to us or help us find her," the mother said in front of a cluster of news microphones and cameras.

The van Dams told reporters they had pooled the funds themselves, with the help of relatives, in hopes of generating "any legitimate information" that can lead to the return of their missing 7-year-old.

Hours later, San Diego bail bondsman George "King" Stahlman announced a $50,000 reward for any tip that results in the arrest and conviction of whoever is responsible for Danielle's disappearance.

A week ago, a Beverly Hills-based charity called the Millennium Children's Fund announced a $10,000 reward for information leading to Danielle's return.

While the focus of the probe has remained on Westerfield -- whom officials have called the only possible suspect they've identified -- the missing girl's parents have had to answer to innuendo about their personal behavior.

Asked on such programs as "Good Morning America" and "Larry King Live" about reports that they have engaged in spouse-swapping, the couple expressed regret that people would focus on anything other than their daughter's return.

While declining to directly address the validity of the rumors, they have dismissed any suggestion that their lifestyle could have been a factor in Danielle's disappearance.

"Absolutely not," they said when asked if the schoolgirl could have been seized by a stranger who might have gotten access to the family home during a swingers' party.

Police have repeatedly said they do not consider the parents suspects in the girl's disappearance -- officially considered a case of abduction -- though they point out that no one has been completely ruled out.

The van Dams said they took a lie-detector test at authorities' request and "passed it."