Saying extreme religious beliefs cannot be a measure of whether a person is delusional, attorneys for Brian David Mitchell tried Monday to have two religious experts blocked from testifying at the accused kidnapper's upcoming competency hearing.

"The evidence is irrelevant to Mr. Mitchell's competence," defense attorney Audrey James said.

A federal judge listened to arguments regarding three motions filed by Mitchell, accused of kidnapping Elizabeth Smart, to have people excluded from testifying at his competency hearing when it resumes Nov. 30.

The motions aim to exclude Dr. Michael Welner from testifying; the writings of polygamist leader Ervil LeBaron, and testimony from Richard Forbes and Daniel Peterson; and the testimony of all lay witnesses.

LeBaron was the head of a polygamous cult believed to be responsible for murders in Utah and several other states who was never found incompetent to stand trial. Forbes is a former head investigator for the Salt Lake County Attorney's Office and helped lead the murder investigation and subsequent conviction of LeBaron. Peterson is a local college religion professor.

Forbes is expected to testify that Mitchell's book, "The Book of Immanuel David Isaiah," is similar to LeBaron's "The Book of the New Covenant." His testimony, combined with Peterson's, will show that Mitchell's religious beliefs are grandiose, but not delusional, according to prosecutors.

"While it's certainly grandiose, it's not out there somewhere," argued Assistant U.S. Attorney Richard Lambert.

Prosecutors say "The Book of Immanuel" is well-thought-out and organized. And because Mitchell won't talk to mental health evaluators, they need to use other tools to determine his competency.

"If he is delusional, if he's just completely out in left field, that's where we're going to find it," Lambert said.

But the defense counters that it's possible for a person to have a delusion but not be functionally impaired.

James said any similarities between Mitchell and LeBaron are irrelevant.

"A nexus between Mr. Mitchell and Mr. LeBaron doesn't exist," she said.

Forbes and Peterson are not mental health experts and not qualified to say if Mitchell has a mental illness, the defense argued in court.

Welner, a renowned forensic psychiatrist from New York City, is expected to be the government's key witness. His 206-page report is believed to be the most extensive study of Mitchell to date, and states he is competent to stand trial.

But defense attorneys are critical of Welner's report, saying it "is just flat wrong."