A tent and shacks are shown Friday in the backyard of a home in Antioch, Calif., where authorities say kidnap victim Jaycee Lee Dugard lived. (Paul Sakuma/Associated Press)The California man accused of kidnapping an 11-year-old girl and holding her captive for nearly two decades is now being investigated in the killings of several prostitutes.

Authorities executed a search warrant at Phillip Garrido's Antioch home, northwest of San Francisco, on Friday, Capt. Daniel Terry of the Contra Costa sheriff's office said. Officials are hunting for evidence tied to the cases of several slain women whose bodies were dumped in an industrial park near where Garrido worked in the 1990s.

The search came as Garrido and his wife, Nancy, pleaded not guilty to charges that include forcible abduction, rape and false imprisonment.

This family photo from Carl Probyn shows his stepdaughter, Jaycee Lee Dugard, who went missing in 1991. (Associated Press) Phillip and Nancy Garrido were arraigned Friday on 29 counts and are being held without bail. Garrido appeared unresponsive as he appeared in El Dorado Superior Court, while his wife cried and put her head in her hands several times.

They are accused of abducting Jaycee Lee Dugard from a South Lake Tahoe, Calif., street in 1991. Authorities say they held her and two children she had with Garrido as prisoners in a backyard encampment.

In 2006, a neighbour had reported that people were living in tents in a backyard encampment at Garrido's home.

A deputy interviewed Garrido, who was given a warning about a bylaw violation. But the officer did not search the yard.

Contra Costa County Sheriff Warren Rupf said the secret encampment may have been discovered if the deputy had shown more curiosity.

They "missed an opportunity" and there are "absolutely no excuses," Rupf said, apologizing to the Dugard family.

Garrido claims to have 'heartwarming story' to tell

Meanwhile, Garrido told Sacramento television station KCRA-TV that he has a "powerful" story to tell.

"You're going to be really surprised with what happened," Garrido said in a telephone interview from the El Dorado County jail where he is being held. "It's a powerful, heartwarming story."

Dugard had been held for almost 18 years in her suspected abductor's suburban backyard compound about 320 kilometres away in Antioch, police said Thursday.

They said Dugard was raped by her abductor, who fathered two children with her. Her daughters are now 11 and 15 and were also kept hidden in the two sheds and tents receiving electricity from a single extension cord.

Fanatical religious beliefs

"You'll hear a powerful story from the victim, you wait," Garrido said. "If you take this a step at a time, you'll fall over backwards and in the end you're going to find the most powerful story — something that needs to be understood."

Phillip Garrido looks out at the courtroom during his arraignment in El Dorado Superior Court in Placerville, Calif. on Friday. At left is his court-appointed lawyer, Susan Gellman. (Rich Pedroncelli/Associated Press) Garrido's interview was at times rambling and incoherent. People who know Garrido told The Associated Press he had become increasingly fanatic about his religious beliefs over recent years.

Dugard was found after Garrido was spotted Tuesday with two children as he tried to enter the University of California's Berkeley campus to hand out religious literature. Officers said he was acting suspiciously toward the children.

They questioned him and did a background check, determined that he was a parolee and informed his parole officer.

Garrido was ordered to appear for a parole meeting and arrived Wednesday with Dugard, who identified herself as Allissa, along with his wife and two children. Corrections officials said Garrido admitted kidnapping Dugard.

Registered sex offender

But Garrido told KCRA-TV he had not admitted kidnapping Dugard. He added that his life has turned around since the birth of his first daughter.

"I tell you here's the story of what took place at this house, and you're going to be absolutely impressed. It's a disgusting thing that took place from the end to the beginning. But I turned my life completely around," he said.

Garrido is a registered sex offender on federal parole for rape and kidnapping convictions.

Authorities said they do not know whether Dugard's daughters were abused, but they are investigating.

'His fun is over'

Dugard's stepfather, Carl Probyn, said he found it "sick" that Garrido had given an interview only hours after his arrest.

"I mean, he's destroyed our lives," Probyn said. "I really haven't got much to say to him other than his fun is over."

Probyn had been a long-time suspect in the case.

Probyn had told police in 1991 he saw someone reach out of a car and grab Dugard before speeding away. He jumped on a bicycle to pursue the vehicle before calling 911.

"It broke my marriage up. I've gone through hell, I mean I'm a suspect up until yesterday," Probyn said.

He said he had lost hope that he would ever see his stepdaughter again but is "delighted" at her return.

Probyn told CBS's Early Show on Friday morning he spoke to his wife — from whom he is separated — after she reunited with Dugard and everyone was "doing great."

"This is an absolute miracle to get her back, and get her back alive, and she is fairly healthy," Probyn said. "My wife says she looks almost like she was when she was kidnapped."

With files from The Associated Press