The picturesque county of Santa Clara, at the southern end of San Francisco Bay, is home to Silicon Valley and 3,000 sex offenders.
Policing sex offenders falls into the hands of 25 law enforcement officers who are part of a federally-funded task force called Sexual Assault Felony Enforcement, or SAFE.
"These are people who have just gotten out of prison or jail who are likely to reoffend," said Santa Clara County Sheriff Laurie Smith. "The recidivism rate for sex offenders is the highest of any type of crime."
Random visits are carried out to confirm that sex offenders who are considered to have a high propensity to commit another assault are living where they say they are and are obeying the detailed conditions that accompanied their early release from prison.
"Sometimes you'll see terms of probation that will include that they can't possess children's toys if their crime was a sex crime involving a child, or can't possess children's clothing," Smith said. "I've even seen terms and conditions of parole or probation that include 'can't possess a puppy or kitten.' We'll be looking at all those things. There is certainly a pornography prohibition."
"Nightline" accompanied SAFE on a typical day on the job, monitoring and tracking sex offenders. The first stop was the home of a 62-year-old former classroom assistant, who served a five-year prison sentence for multiple crimes against a 10-year-old girl.
After clearing the location, identifying the parolee, the police began the search. ABC News obtained permission from the parolee to follow the police onto his property to film their work.
While the police searched, we asked the parolee about his original offense.
"The original offense was the hug of the student," he said. "I worked with this student throughout the whole year and we developed a friendship during that time. ... She had low self esteem -- more so than any of the other members in class."
When we asked if it was possible by providing her with gifts, she was being groomed, the parolee said, "That's sort of the stereotypical view that was taken. I think that's part of [what] threw me into a category like a pedophile category."
Police Sweep Sex Offenders' Homes
The SAFE team searched his apartment for two hours. Sifting through the mountain of clutter in every room was a labor-intensive task.
"It makes it a lot tougher for us when we go in and search a residence if there is more stuff that we have to dig through," state parole agent Greg Weber said. "A lot of the stuff that we discover is not necessarily on the surface or in plain sight, but we'll have to dig."
This sex offender had been on parole for more than two years at the time of the SAFE sweep. It was only the police's second visit to his home, but he told us the visit was "overkill."
Although he was found guilty for the lewd and lascivious acts with a child under 14, possession of obscene matter depicting a child in a sexual act, and annoying and molesting a child, the parolee maintained his innocence.
Despite his attempt to play down the offenses, the parolee must also wear a GPS tracking device to ensure he's never in a location that places him close to children. Another condition of his parole explicitly forbids possession of any toys or children's clothing.
During the search, the police located a collection of toys in his home, and an Obi Wan Kenobi kid's costume.
"I bought that about a year and a half ago," the man said. "It was for a costume party over at my dad's assisted living place. He's 94."
When the officers questioned the parolee about the child's costume, he claimed he had purchased it to wear himself.
"You could put that on a person, on a guy. I had a shield and a helmet, a Trojan helmet," he said. "I didn't buy it for a child."
Despite his denials, the officers determined that the costume is a clear and certain breach of his parole. The man was taken into custody by police.
As they prepared to take this parole violator back to jail, we asked the obvious question: Was he planning to groom a child with the toys?
"No, those were just some of the things we've had over the years," he said.
The SAFE team may have prevented him from sexually abusing another child; he only had five months to go before he would be released from all his parole conditions.
"Once this supervision is gone and once no one is looking over his shoulder supervising him, then he's on his own. So that's worrisome to me," Weber said. "But all we can focus on right now is while they're under our jurisdiction."
Smith is skeptical that sex offenders can be rehabilitated.
"We find that the same people commit the same kinds of crime," she said. "We believe that they'll reoffend."
Jaycee Dugard Case: 'Tragic' for Law Enforcement
The case of Jaycee Lee Dugard, who was allegedly kidnapped at 18 and forced to conceive two children by captor Philip Garrido, has been a chastening one for the state of California. Though Garrido, a known sex offender, was visited by a parole officer, Garrido's backyard -- where Dugard was held -- was never checked.
"It's a tragic case. Could things have been done differently? Absolutely," Smith said of the case, which occurred just outside her jurisdiction. "And I think that's why this team is so important. To make sure things like that don't happen in the future."
Back on the road, SAFE headed for another address, but not all parolees are easy to find. More than 63,000 people are required to register as sex offenders in California, which is home to approximately 83,000 sex offenders.
Although Santa Clara County has a compliance level of 95 percent, many offenders are registered as transient and others simply disappear.
"He was living here since 2008 up until Jan 1. Then he left ... [without informing] his probation officer or complying with [California law] and registering within five days of moving," a SAFE team member told us about the next offender on their sweep list.
At a third house, the family members told police that the parolee was not there.
"Very often, family members are very savvy with the troubles that their loved one, father, brother, have been in. And so they're ready to lie," Santa Clara Deputy District Attorney Dan Okonkwo said. "We keep coming back to check up."
As the day drew to a close, we learned of a second arrest: a parolee with prohibited pornographic material and something the officers had never seen before.
"There were numerous photos of anime -- pornography which is not technically pornography. It's cartoon characters, most of which involved pre-pubescent males involved in sexual acts with adult males. There was some adult pornography, which is in violation of his parole," a SAFE investigator said. "But given his particular offense involving minors ... the material we found was very disturbing."
The police said the pornographic material suggested the parolee was still set in his ways.
"With someone with his history of committing acts similar to that of children of that age, just by him viewing this, it's pretty obvious the attraction is never going to go away," the investigator said.
The sex offender was booked again and sent to jail. Outside of supervision, the cop said that development would likely have gone unnoticed.
"If there is nobody to watch him and nobody to catch him at the early stages of this, that's just going to spiral out of control until who knows what," he said.
The statistics against sex offenders are damning; most will repeat their offences, even if they've served time in jail. But Smith said we should not be writing these people off.
"I have a lot of compassion for them. I don't want them offending again," Smith said. "And if there are steps we can do in law enforcement to keep them from offending, especially sex crimes, I think that's what we need to do."
Of the 20 visits today, most were found to be complying with their conditions. Two were not and are now back in jail. The SAFE team closes down for the night, knowing there'll be plenty of work come morning.