FARGO - Authorities want to know why a convicted sex offender and fugitive from Indiana moved here and when, after a tip from a neighbor who saw his picture on "The Oprah Winfrey Show" led to his arrest.

William C. Davis, 33, of Wadesville, Ind., who was on the FBI's Most Wanted Fugitives list, was arrested Thursday in the one-bedroom upstairs apartment where he was living. He faces felony charges of molesting three Indiana boys last year and failing to register as a sex offender. He was convicted of child molestation in 1992.

Karie Miller, 29, a Fargo deli worker and mother of three, alerted the FBI after her friend, Jean Rosenthal, of Moorhead, Minn., recognized Davis as a man she knew as "Mark," who lived in the unit above Miller and her family. Rosenthal called Miller, who was shocked when she confirmed the match on Winfrey's Web site.

"I can't believe he was around my kids," Miller said Friday. Davis told her he had come to Fargo from Kentucky to look for work, she said.

Miller said she helped Davis find a place to live after meeting him at a Moorhead apartment building where her brother lived and where Davis worked as a maintenance man.

"He was a carefree person who had this dopey, innocent look," Miller said. She also helped him with cooking and laundry after he broke his leg a few weeks ago, she said.

Miller said Davis cried when he called her from jail after his arrest, telling her he could not believe she had turned him in. She said she told him, 'Dude, I don't even know your real name.'"

Davis' arrest in Fargo comes less than three months after convicted sex offender Joseph E. Duncan III was apprehended in Idaho and charged with killing three people. Duncan had lived in Fargo before fleeing authorities in April.

Police Chief Chris Magnus acknowledged that the Duncan case has put many people on edge.

"Frankly, I think it's a good thing if the community is a little more alert and vigilant," he said. "That may have made the difference in this case."

Authorities said they do not know if Davis knew anyone in the Fargo area. Duncan had been befriended by a Fargo doctor who invited him to North Dakota, Magnus said.

"There's sex offenders in every community in this country," Magnus said. "Everybody could pick a place if they're trying to escape scrutiny. I don't think there's anything unique about our community."

Davis, who was convicted of child molestation in January 1992, is accused of molesting boys from January 2004 to July 2004. He failed to comply with Indiana's sex offender registration laws and disappeared in the summer of 2004, authorities said.

Davis was one of several fugitive sex offenders shown on Winfrey's program Tuesday. A $100,000 reward, offered by her production company, applies to fugitives presented on the show and on www.oprah.com.

Miller and Rosenthal planned to split the reward money, Miller said.

FBI Special Agent Paul McCabe said authorities believe Davis has been in the area since January or February, but they are still investigating his movements.

"It takes a lot of courage to call in with information," McCabe said. "We encourage people to call, no matter how valuable they think the information is."

McCabe said the incident shows Winfrey's popularity.

"She really stepped up to the plate by offering that reward," he said.