A Pennsylvania man and his son were arrested Thursday on charges of harassing Sarah Palin's family and lawyers in a case a prosecutor said went beyond "merely creepy to truly threatening."

Craig Christy, 47, and his son, Shawn Christy, 19, were placed under arrest at the FBI office in Allentown. The pair were indicted by a federal grand jury in Alaska on Wednesday.

They are accused of harassing members of the former Alaska governor's family as well as her attorneys and employees of the law firm. Palin, the 2008 Republican vice presidential nominee, is also a possible presidential candidate.

U.S. Magistrate Judge Arnold Rapoport ruled Thursday that Craig Christy and his son, Shawn Christy, will be held in custody and sent to Alaska to face the charges.

The pair made hundreds of threatening calls, according to Assistant U.S. Attorney John Gallagher.

"There's a level of obsession here that elevates the conduct from merely creepy to truly threatening," Gallagher said in arguing for their detention.

Marc Fisher, Shawn Christy's attorney, argued his client did not pose a danger to the Palin family.

"There's no indication of any threat, no indication of any violence," he said.

Rapoport declined a request by Fisher and Michael Brunnabend, Craig Christy's lawyer, that the father and son remain free and report to Alaska themselves.

A magistrate in Alaska had previously issued restraining orders against both men.

Karen Christy, Craig Christy's wife and Shawn's mother, said in an interview Thursday that the family has been persecuted by the Palins and law enforcement officials for more than two years.

They contend Sarah Palin and her daughter, Willow, sent sexually oriented text messages to the teen in 2009.

"All of these things have been happening to my family, and the police and the FBI and the federal agents don't seem to (care) ... about going after Sarah Palin because she's a big political figure," Karen Christy said.

She denied the family is a threat to Sarah Palin, and said Craig and Shawn made the recent phone calls to try to locate an original copy of a letter threatening Willow Palin that was submitted as evidence against Shawn earlier this year. Shawn Christy said he had no involvement in the letter.

"We're obsessed because we're just trying to get the truth out there, and we're just trying to defend ourselves in the only way we can," Karen Christy said.

Palin has said she feared Karen and Craig Christy because they wrongly believe she had a sexting relationship with their son two years ago. Recordings of telephone calls made to Palin's attorney by Shawn Christy are peppered with profanity-laced tirades and vows to continue calling nonstop.

Craig and Shawn were invited by the FBI for an interview Thursday morning and then taken into custody.

The family lives in McAdoo, Pa.

Palin's attorney, John Tiemessen, did not respond to an emailed request for comment.