FARGO - The arrest of Joseph Edward Duncan III, a registered sex offender and college student who was found with an 8-year-old girl in Idaho, surprised police here who had been looking for him since May.

Duncan, 42, was arrested in Coeur D'Alene, Idaho, on a kidnapping charge Saturday after he was spotted at a restaurant with Shasta Groene, who disappeared with her brother six weeks ago from a home where family members were bludgeoned to death.

"We didn't have any information that suggested he would be connected with the homicides or the missing children in Idaho," Fargo Assistant Police Chief Keith Ternes told reporters Saturday.

Duncan has a long criminal history, including a 1980 sexual assault of a 14-year-old boy at gunpoint in Washington state. He moved into an apartment in north Fargo in 2000, after registering as a sex offender.

Police Capt. Jeff Williams said Duncan followed the rules required of high-risk offenders, and neighbors said he kept to himself.

"As far as we know, he was more or a less a model," Williams said.

That changed after Duncan was charged with molesting a 6-year-old boy at a middle school playground in Becker County in Minnesota last year. He was released on bail in April and left the area in May without notifying authorities.

A federal arrest warrant for Duncan was filed in federal court in Minneapolis on June 1, FBI spokesman Paul McCabe said.

Police last visited Duncan's apartment on May 5 with a search warrant, Ternes said. He said he does not believe Duncan ever returned to Fargo after that.

Ternes said police had information that Duncan might be "well west" and out of the area, but nothing that would lead them to Coeur D'Alene. Authorities also monitored a Web site created by Duncan, but it yielded no clues on his whereabouts, Ternes said.

Kootenai County Sheriff's Capt. Ben Wolfinger Duncan's Web site, fifthnail.com, was down Saturday but could be seen in archived Web pages.

The name was derived from a myth involving a fifth nail that was crafted for Christ's execution but that was not used after gypsies hid it from Roman soldiers. "The Fifth Nail is the nail that was meant to pierce the Heart of Christ and end his suffering," the site said.

In one posting, he said he knew his 1980 sex offense was wrong, "but I can honestly say that I had no clue of the impact my actions would have on my victim, or society, or myself. … I was abused, even raped, so often and by so many different people growing up that I thought it was like smoking pot, everyone did it, but nobody openly admitted it."

In another, he said as a teen he was sentenced to a group sex offender program "where half the men in my 'treatment group' sat and fantasized about me." He said forcing sex offenders to register was discriminatory.

Police had checked on Duncan on a quarterly basis and his apartment was searched at least twice during the Becker County investigation, Ternes said.

Duncan enrolled at North Dakota State University in the fall of 2000, and was still listed as a student during the spring semester this year, school spokesman Dave Wahlberg said.

Wahlberg said he could not discuss details about Duncan at NDSU, citing privacy rules, but he said Duncan had no record of problems with campus police.

Duncan was a member of Phi Kappa Phi honor society and made the dean's list twice, in fall 2000 and spring 2001, Walberg said.

Bryan and Jodi Watters, who have lived in Duncan's Fargo neighborhood for 10 years, said they heard about a sexual offender moving in across the alley, but never talked with Duncan.

"I think he rode a bike a lot," Jodi Watters said.

"That's scary," she added, looking at Duncan's apartment complex, "when he lives back here."

Jean McCrowell, who lives in a nearby apartment, said she joined some people in Duncan's building for a group rummage sale last fall, but she did not remember meeting him.

The neighborhood has several apartment buildings and older homes that have been converted into apartments. It's a mixture of college students and families, residents said.

"Each apartment house has its separate little culture and people do take care of one another," McCrowell said.

Kerstin Haugen, who lives in an apartment building next door to Duncan's, said she had not seen him for several months. Police had stopped by looking for him, she said.

"He seemed normal," Haugen said.

Duncan apparently left behind two cats when he left. A resident of his apartment complex, who refused to give her name, said she cared for the animals before bringing them to a shelter.

"He was very protective of his cats," she said.

The woman said she considered Duncan a friend and said he never caused trouble in the neighborhood.

"There are kids all over this neighborhood," she said.