San Francisco  - Police dogs working on the property of the alleged kidnappers of Jaycee Dugard have identified an area of possible human remains, the authorities revealed Friday.

Two cadaver dogs working independently of each other indicated the same area, which police will now probe with ground-penetrating radar. Police believe that the alleged kidnappers, Phillip and Nancy Garrido, could be implicated in the disappearance of two other young girls in the years prior to Dugard's abduction.

One bone already found on their property has been identified as human, while another bone found earlier this week is currently undergoing evaluation.

Alameda County Sheriff's Department spokesman Sergeant JD Nelson said two dogs "indicated" a site in the backyard. But he cautioned that the area is known to have buried remains from Native Americans and animals.

The Garridos have pleaded not guilty to all 29 charges of kidnapping Dugard in 1991 when she was 11, and keeping her in captivity for 18 years. Garrido is also accused of siring two daughters with Dugard.

Garrido came forward with his victims last month after a suspicious campus police officer alerted his parole officer.

Also on Friday, the first official pictures were released from the Garrido home, showing squalid living conditions including rotting piles of trash in the house, an open sewage pit and a toilet that emptied straight into the ground. Though the property is now closed as a crime scene, county investigators have also slapped it with a closure notice for being uninhabitable.  dpa