California police have entered a kidnapping crime scene with shovels and other digging equipment as they expand the scope of their search for clues to the 18-year captivity of Jaycee Lee Dugard, who was snatched outside her home when she was just 11.

Police officials entered the crime scene wearing masks and wielding chainsaws, preparing to clear out bushes and trees to help dig through the backyard in an apparent attempt to clear a path to a neighboring house.

Authorities earlier expanded the boundaries of the crime scene to include the house next to one owned by Dugard's alleged abductors, Nancy and Phillip Garrido.

The Garridos are charged with kidnapping 11-year-old Jaycee Lee Dugard in 1991 and holding her in an intricate backyard compound of tents, sheds and fences in their backyard, where police say she was repeatedly raped and bore two children by her captor.

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Neighbors identified Damon Robinson as a resident of the house next to the Garridos. Robinson has said he lived there for more than three years — and it was his then-girlfriend who in 2006 called police after she saw the tents and two children in the backyard. He didn't return a telephone call after his home was declared a crime scene.

Dugard's stepfather Carl Probyn told FOX News' Geraldo Rivera that his daughter, now 29, is fragile and said he did not think she had tried to escape the backyard compound during her captivity.

"She survived 18 years. If she tried to climb the fence every day, she wouldn't be here today," Probyn said.

Probyn told FOX News that Jaycee is "an extremely good mother" and that his grandchildren were homeschooled by Garrido. He said the children, now 11 and 15, just found out that Jaycee was kidnapped.

"They thought he was their dad. They didn't know Jaycee was kidnapped. She told them two days ago."

Probyn says he's unsure if his daughter loved Garrido, but she "definitely was bonded to him after 18 years."

"The girls are attached to him ... it's going to take years to debrief her. People don't realize you can't just change after 18 years."

Garrido and his wife pleaded not guilty to a total of 29 counts, including forcible abduction, rape and false imprisonment. Garrido appeared stoic and unresponsive during the brief arraignment hearing. His wife cried and put her head in her hands several times.

Garrido gave a rambling, sometimes incoherent phone interview to KCRA-TV from the county jail Thursday in which he said he had not admitted to a kidnapping and that he had turned his life around since the birth of his first daughter 15 years ago. He told the television station that he walked into the FBI's San Francisco office on Monday with Dugard's daughters and dropped off several documents containing rambling passages about religion, sexual compulsion and mind control.

FBI spokesman Joseph Schadler confirmed Garrido left the documents with the agency, but declined to discuss any further details.

Garrido was required to register as a sex offender because he was convicted in 1977 of kidnapping a 25-year-old woman from parking lot in South Lake Tahoe, the same town Jaycee Dugard lived in when she was snatched from a school bus stop.

He was convicted of raping the woman multiple times at a Reno storage unit that the investigator from the case described as a "sex palace." It featured various sex aids, sex magazines and videos, stage lights, wine and a bed, said investigator Dan DeMaranville.

Gail Powell, spokeswoman for the Nevada Department of Public Safety, said Garrido met his wife while he was serving time for the rape at the federal penitentiary in Leavenworth, Kan.

He served about 10 years of a 50-year federal sentence for kidnapping, and less than a year for a concurrent Nevada sentence of five years to life in prison for sexual assault. He was paroled in 1988, said Nevada Department of Corrections spokeswoman Suzanne Pardee.

A violation of Garrido's parole conditions sent him back to federal prison from April to August of 1993. Dick Carelli, spokesman for the federal Office of Court Administration, did not know what Garrido did to violate parole. Authorities are trying to piece together how and by whom Dugard was held during Garrido's four-month absence.

Hinkle said the alarm raised by the neighbor who contacted the sheriff's department never was relayed to Garrido's parole agent. But there was no ban on him having contact with children, nor restrictions on his travels.

Monica Adams, 33, whose mother lives on their street, said she knew Phillip Garrido was a sex offender and that he had children living with him. Other neighbors knew, too, but they assumed police were keeping tabs on him.

"He never bothered any one, he kept to himself," Adams said. "What would we have done? You just watch your own."

Probyn said he was frustrated to find out that a car matching the description of the one he saw speeding Dugard away in the day she was kidnapped was found in the yard of Garrido's home. Nancy Garrido also fits the "dead-on" description he gave of the woman who pulled her into the car, he said.

"He had every break in the world," Probyn said of Garrido's close encounters with the law.

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The Associated Press contributed to this article.