This undated file photo obtained from the FBI shows Jaycee Lee Dugard, who was kidnapped when she was only 11.

A Californian couple has denied kidnapping an 11-year-old girl and keeping her as a sex slave for 18 years as questions mounted over how their alleged crimes went undetected for so long.

Phillip Garrido, 58, and his wife Nancy, 54, pleaded not guilty to 29 alleged offences including kidnapping, rape and false imprisonment, following the discovery of Jaycee Lee Dugard on Wednesday, nearly two decades after the blonde schoolgirl was snatched outside her home in 1991.

Dugard, now 29, was confined in a makeshift prison of sheds and tents in what police have described as a “backyard within a backyard” at Garrido’s home in Antioch, around 50 miles (80 kilometers) east of San Francisco.

On Thursday, police revealed that convicted rapist and registered sex offender Garrido had abused Dugard and fathered her two daughters, now aged 15 and 11, who had also been kept in the compound.

In an interview with a local television station, Garrido acknowledged that his abduction of Dugard from outside her South Lake Tahoe home in 1991 had been a “disgusting thing.”

But Garrido, described by neighbors as a religious fundamentalist who wanted to set up his own church, insisted he had “turned his life around” since kidnapping Dugard and that the case was a “heart-warming” story.

Dugard meanwhile was reunited with her mother and half-sister at a motel outside San Francisco on Friday. Her former stepfather Carl Probyn said Dugard was struggling to come to terms with what had been inflicted upon her.

“Jaycee feels that she has real regrets for bonding with this guy,” Probyn told reporters outside his home in Orange, south of Los Angeles.

Experts said it could take years for Dugard to recover.

“I’m very concerned about her condition and her ability to heal,” said Alison Walls, a clinical psychologist at the University of the Rockies. “She will really need to be in a trauma program and treated by specialists and it will take a long time.”

Dugard was found after police reported Garrido acting suspiciously at the University of California, Berkeley, where he was trying to hand out religious literature propounding claims he was able to channel the voice of God.

He was summoned to a meeting Wednesday with his parole officer who, having previously visited the Garrido home, found it strange that in addition to his wife Nancy he brought along two girls and a woman he called “Allissa.”

Dugard’s real identity emerged during the course of the meeting and Garrido and his wife Nancy were detained.

Nancy Garrido sobbed throughout a five-minute court hearing on Friday while her husband stood expressionless nearby. Both entered not guilty pleas through defense attorneys.

Meanwhile neighbors of the Garridos expressed shock that the secret prison could go unnoticed for so long.

“It’s kind of embarrassing to be here this long and not know what’s going on. How could that go on under all of our noses?,” one neighbor, who gave his name only as Steve, told AFP.

“When I first met him (Garrido) I thought he was a nice guy. Now I’d just like to see him shot or hung.”

Police in Contra Costa County meanwhile admitted that they had received a tip in November 2006 that children were living in Garrido’s backyard, but failed to follow it up properly.

Sheriff Warren Rupf issued an apology over the missed opportunity to rescue Dugard, saying law enforcement officials were distraught over their failure to discover Garrido’s crimes earlier.

“I can’t change the course of events, but we are beating ourselves up over this and are the first to do so,” Rupf said.

The sheriff confirmed that neighbors called 911 on November 30, 2006, to warn that children were living in Garrido’s home and that people appeared to be housed in the backyard.

However the sheriff’s deputy who responded to the call never entered the house or checked the backyard, Rupf said, missing an opportunity to rescue Jaycee.

Garrido served time in federal and Nevada state prisons from 1977 to 1988 in connection with a kidnapping and sexual assault he committed in November 1976, The Los Angeles Times reported.

He had been sentenced to 50 years for a kidnapping she believed occurred in the South Lake Tahoe area and involved crossing state lines, according to the paper.

He was given five years to life for the sexual assault but was paroled to California 21 years ago.

Source: AFP