A nondescript bungalow in a quiet rural neighbourhood, the house at 1554 Walnut Avenue looked like any other in the blue-collar former mining town of Antioch, east of San Francisco.

Yet behind an eight-foot-high wooden fence, a network of ramshackle sheds and tents at the rear of the property formed a horrific secret prison for kidnapped schoolgirl Jaycee Lee Dugard for 18 years.

It was here that Dugard - abducted by convicted rapist Phillip Garrido in 1991 - was held captive and impregnated by the man whom neighbours described as a religious fundamentalist who often preached from his front yard.

Ms Dugard was discovered alive on Wednesday. It later emerged that she had had two daughters aged 15 and 11 with Garrido while held captive.

Yesterday, stunned neighbours of Mr Garrido expressed shock at the crimes that had taken place on their doorsteps and disbelief that they could have gone undetected for so long.

One neighbour, Steve, who asked to be identified only by his first name, said he had seen the children fathered by Mr Garrido, 58, on a handful of occasions in the past two decades.

"As far as I thought, they were nieces or something," he told AFP. "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?

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

The neighbour said that Mr Garrido could often be seen out in his front yard preaching.

Meanwhile, the kidnapping charges against Mr Garrido and his wife Nancy came as a California sheriff said they had "missed an opportunity" nearly three years ago to save Dugard.

Someone called 911 on November 30, 2006, to say that a woman and young children were living in tents in the backyard of Phillip Garrido, a registered sex offender, said Sheriff Warren E. Rupf of Contra Costa County, California, yesterday.

"This is not an acceptable outcome," he said. The responding sheriff's deputy spoke with Mr Garrido in the front yard of his house.

"None of us, particularly law enforcement, should believe a word that one of these animals utters," Mr Rupf said when asked about the lessons learned from the missed opportunity. "If there's a sophistication [about sex offenders] in any regard, it's in misrepresenting who they are and what motivates them.

"We took things he said obviously at face value and did not properly brand him."