TACOMA, Wash. -- Pierce County sheriff’s detectives went on a raid Thursday rounding up sex offenders who they said were scamming the system.

Detectives went after level-three sex offenders who registered as transients, but in fact live in homes.

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Thomas Hall, 43, was one of those sex offenders arrested during the raid. In 1990, Hall was convicted of raping a woman. He is required by law to register as a sex offender, which he has been doing, but police said like many sex offenders, Hall claims he is homeless.

With that claim, none of his neighbors has been notified that there is a convicted rapist living next door.

“He's been here for 10 years I think. I don't know. That's all I know, that's what he told me. I didn't know he was a sex offender,” said Hall’s neighbor Ko Chaykhame.

Detectives conducted weeks of surveillance to prove that Hall and others like him falsely claim they are transients.

Fred McFate, 27, is a level-three sex offender convicted of child molestation. He registered as homeless, but has been living in an apartment complex right next to small children, detectives said.

“We've sat here and talked with him and had barbeques and stuff. I mean you'd have never known it by talking to him and stuff he just seemed like a nice quiet kind of person,” said McFate’s neighbor Jim Hoag.

Dustin Case, 20, was convicted of molesting two young boys in 2004 and admitted molesting other children as young as 2 years old.

Case has allegedly been living in a Tacoma home for months, all the while claiming he was homeless.

In the home, detectives found an 18-month-old child identified as Case's son.

Investigators said because he continually lied about being a transient, the sheriff's department had no idea this convicted child molester was now living with a young child of his own.

The child was taken into the custody of Child Protective Services and detectives said the mother, Case's girlfriend, was under the legal age of consent when she became pregnant.

Right now, there are 2,855 registered sex offenders in Pierce County alone. Nearly 100 of them claim to be homeless, but investigators said they believe most of them are lying.

Detectives said they will continue to investigate wrongly registered sex offenders.

“The neighbors have the right to know they are there. The neighbors probably will not be happy about having that kind of person in their neighborhood,” said Sheriff Paul Pastor of the Pierce County Sheriff’s Department.

All of the men arrested on Thursday face charges of failing to register as a sex offender and prison time.