By NICHOLAS K. GERANIOS
The Associated Press
Wednesday, July 6, 2005; 11:09 PM

COEUR D'ALENE, Idaho -- A convicted sex offender accused of kidnapping 8-year-old Shasta Groene and her brother is also believed to be responsible for the May killings of three people at the family's home, authorities said Wednesday.

"When we get the pieces together, we'll find out what the motive is," Kootenai County Sheriff's Capt. Ben Wolfinger said at a news conference.

Joseph Edward Duncan III, 42, of Fargo, N.D., a fugitive from an earlier child molestation charge, was arrested Saturday at a Denny's restaurant with Shasta, believed to be the sole survivor of the attack and its aftermath.

The bodies of Shasta's mother, older brother and mother's boyfriend were found May 16, bound and bludgeoned at the home outside Coeur d'Alene, and authorities have said they believe her 9-year-old brother, Dylan, also is dead.

Their father, Steve Groene, held a news conference Wednesday in which he said Shasta, who remains hospitalized at the Kootenai Medical Center here, is doing well.

"That's certainly more than we could have hoped for. She's very upbeat, seems to be pretty healthy, and she's really glad to be home," Groene said.

Groene also expressed frustration that Duncan was allowed to be free despite his sex crimes record, and he urged people to demand action from their elected officials.

"People need to get on their congressmen, their senators and even the president. This needs to change, now," he said.

Washington state passed an involuntary commitment law for violent sexual predators in 1990; an evaluation of Duncan upon his release from a Washington prison in 2000, however, found there wasn't enough evidence he would be a repeat offender.

Groene had a new tattoo on his upper left arm marking the death of his older son in the mid-May attack: "In loving memory, Slade Vincent, 13."

Duncan has been charged only with kidnapping, which can carry the death penalty or life in prison. Wednesday was the first time authorities have said they believe he is also responsible for the three deaths.

Human remains found in western Montana, believed to be the boy, will probably not be conclusively identified until next week, Wolfinger said.

Sheriff Rocky Watson told KREM-TV of Spokane, Wash., on Wednesday that he believes the slayings were committed so Duncan could acquire the two children for sex.

"I think he's a very meticulous person and he had a very detailed plan," Watson said.

Officials said they have found no connection between Duncan and the family, raising the possibility the attack and kidnapping were random. Wolfinger declined to say whether Duncan had a gun or speculate how he might have overpowered the five people at the house.

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

Misty Cooper, Shasta's aunt, said Shasta "seems to be doing really good right now," but that the family had not spoken to the girl about her ordeal.

"We just go on with everyday, normal things," Cooper said.

Shasta told investigators she was awakened at her home and watched as her 40-year-old mother Brenda Groene, 13-year-old brother Slade and 37-year-old Mark McKenzie were tied up, according to court documents.

Then she and Dylan were bound and taken from the house into a pickup truck, transferred to a stolen red Jeep and taken to the first of three campsites, she said.

Officials allege the children were repeatedly sexually molested during their ordeal.

While it is the Associated Press' policy not to identify alleged victims of sexual assault in most cases, the search for the children and Shasta's recovery were so heavily publicized that their names were already widely known.

Duncan had spent more than a decade in prison for sexually assaulting a 14-year-old boy at gunpoint in Tacoma, Wash. He was a fugitive at the time of his arrest, charged with molesting a 6-year-old boy in Minnesota.

He was released on $15,000 bail earlier this year after being charged with molesting the boy. Fargo police had been looking for him since May, when he failed to check in with a probation agent.