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Idaho Suspect's Chilling Record

Authorities believe the man accused of kidnapping an 8-year-old girl and her brother is also responsible for the May killings of three people at the family home, a sheriff's spokesman said Wednesday.

"We believe Joseph Duncan is the only one responsible for these crimes," Kootenai County Sheriff's Capt. Ben Wolfinger told a news conference.

Joseph Edward Duncan III was arrested Saturday at a local restaurant with Shasta Groene, believed to be the sole survivor of the May 16 attack.

The terrible truth about Duncan is now becoming apparent,

. Twenty five years ago he was declared a sexual psychopath and a danger to others, and now that he's been charged with kidnapping Shasta Groene, he's the latest shocking example of how even a registered sex offender can keep offending again and again.

Court documents going back to 1980 show that Duncan's sex crimes began when he was a teenager, Blackstone reports. At 17 he pleaded guilty to rape and was put into a therapy program for sex offenders.

He told doctors he was just 12 when he sexually assaulted a five-year-old boy. By age 16 he said he had raped 13 different boys.

Doctors evaluating Duncan said "the danger he presents to children is very great," and "he is not safe to be at large."

After 22 months in therapy he dropped out. His doctors reported: "Mr. Duncan has shown an unwillingness to modify his sexually deviant behaviors."

Duncan spent almost 18 years in prison. When he was released in 2000 he moved to North Dakota and, as required, registered as a sex offender. But neighbors didn't know his history.

In 2004, on a Minnesota playground, he was arrested for molesting a six-year-old boy. He was released on bail because he had no recent criminal record, reports Blackstone.

He skipped bail and was a fugitive until his arrest in Coeur d'Alene.

Duncan has only been charged with kidnapping, and Wednesday marks the first time authorities have said they believe he is responsible for the bludgeoning deaths of Shasta's mother, older brother and mother's boyfriend.

The kids' father, Steve Groene, held a news conference Wednesday in which he said Shasta is home and doing well.

Steve Groene said his daughter is "very upbeat" and "seems to be pretty healthy." And he said she's "really glad to be home."

As for her nine-year-old brother, Groene noted that police believe some remains found in Montana are Dylan's. But he said until someone determines that for certain, he'll still believe his son is alive.

On Tuesday, Duncan made his first court appearance on charges of kidnapping Dylan and Shasta Groene. Court documents provided shocking details of the children's captivity, and make even more poignant the security camera video of Shasta and Duncan taken just hours before her rescue.

In a handwritten transcript an investigator gives details of interviews with Shasta.

The court document shows that Shasta told investigators she and her 9-year-old brother were taken to a remote campsite and repeatedly molested.

Although it is CBS News policy to not name victims of sexual assault, the Idaho children's names were widely disseminated before the new allegations.

"This little girl really went through more than any little girl should ever have to think about," Kootenai County Sheriff's Capt. Ben Wolfinger said Tuesday.

Shasta was recognized by a waitress who called police around 2 a.m. Saturday.

"Nobody in the family has ever seen this man before. Ever," said Shasta's grandmother, Darlene Torres, Wednesday on CBS News' The Early Show.

Shasta Groene's statements place Duncan inside the rural home near here where the girl's mother, older brother and mother's boyfriend were bound and bludgeoned to death. Their bodies were found on May 16.

The videotape of Shasta shows a child surviving an ordeal, says child trauma expert Lenore Terr.

"She was holding herself, she was not a regular child — she has been terribly hurt mentally," Terr told CBS News.

Investigators believe the campsite where Shasta and Dylan were held is in rugged country near St. Regis Montana. Human remains found at the campsite have not been positively identified but are believed to be Dylan.

The case was a mystery for almost seven weeks until Duncan for some reason returned to Coeur d'Alene and Shasta was recognized.

The intent of the crimes, court documents said, was to rape, seriously injure or commit a lewd and lascivious act on a child under 16 years old. Duncan has not been charged with anything other than the kidnapping counts, which can carry the death penalty or life in prison.

"Shasta and Dylan were repeatedly molested," Kootenai County Sheriff's Sgt. Brad Maskell wrote in a terse, handwritten affidavit released Tuesday. "Shasta saw Mr. Duncan molest Dylan."

Shasta was awakened at her home and watched as her mother Brenda Groene, 13-year-old brother Slade and Mark McKenzie, her mother's boyfriend, were tied up, the document said. She and Dylan were also bound and placed in the pickup truck. The children were later transferred to a stolen red Jeep and taken to the first of three campsites, she said.

The affidavit does not mention the beating deaths of the girl's family or whether she witnessed the killings. It also did not say if she witnessed what happened to Dylan.

Shasta told officers that Duncan did not have an accomplice. Despite her statement, investigators were still trying to determine if Duncan acted alone, Wolfinger said.

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