Police prepare to dig up Garrido's backyard and, inset, missing girls Michaela Joy Garecht, top, and Ilene Misheloff, abducted in 1988 and 1989.

Police prepare to dig up Garrido's backyard and, inset, missing girls Michaela Joy Garecht, top, and Ilene Misheloff, abducted in 1988 and 1989. Photo: Reuters

US investigators have carried out a fresh search at the home of Jaycee Lee Dugard kidnap suspect Phillip Garrido, seeking evidence in two unsolved child abductions from the 1980s.

About 60 officers with sniffer dogs converged on Garrido's property in Antioch, east of San Francisco, one week after a bone fragment found on a neighbouring property was said to be "probably human."

Police from the towns of Hayward and Dublin, roughly 96km south of Antioch, said the search was related to the disappearance of two young girls in 1988 and 1989.

Police said the search on Tuesday was prompted by similarities between those two disappearances and that of Dugard.

After an all-day search that covered about half the Garrido property, Hayward police lieutenant Christine Orrey said investigators had not found anything directly linking Garrido or his wife to the two disappearances.

Orrey said detectives were looking for evidence tying Garrido to the disappearance of nine-year-old Michaela Garecht, who was snatched outside a grocery store in 1988.

"We haven't located anything earth-shattering at this point," Orrey told a swarm of reporters gathered outside the boarded-up Garrido residence.

But Garecht's mother, Sharon Murch, said that did not dissuade her from believing Garrido could be the one who kidnapped her child two decades ago.

"I think it could be him, there's no doubt it could be him," Murch said. "I know if Jaycee Dugard can be found alive and come home after 18 years, my daughter can be found alive and come home.

"Michaela, if you're out there somewhere, we love you, we miss you, and there's nothing that could have happened in the last 20 years that could have changed that."

Orrey said police had been struck by a number of similarities between the Dugard and Garecht cases after Jaycee was found alive last month, 18 years after her alleged abduction by Phillip and Nancy Garrido in 1991.

"These similarities included the physical appearance and ages of the victims, the manner of the abduction, that they were taken in a very brazen manner in broad daylight in a public place," Orrey said.

There were also similarities between the description of the vehicle used in the 1988 abduction of Garecht and a vehicle found at Garrido's home.

Pictures of Garrido also resembled a police artist sketch of a suspect in the Garecht case, Orrey said.

Dublin police meanwhile told reporters that they were searching for links between Garrido and the disappearance of 13-year-old Ilene Misheloff, who vanished while on her way home from school in 1989.

Lieutenant Kurt Von Savoye told reporters that a description of a vehicle that Misheloff was seen getting into was similar to a sedan found at Garrido's home last month, but acknowledged it was simply "one lead in hundreds, if not thousands, over the decades."

Von Savoye said offenders such as Garrido usually had "multiple victims."

AFP