A psychiatric nurse who observed the man charged with abducting Elizabeth Smart said Tuesday she believes he has faked psychiatric symptoms and behaviors to avoid prosecution and remain at a state hospital.

Leslie Miles, a former employee of Utah State Hospital, testified during the second day of a competency hearing for Brian David Mitchell.

Mitchell, 56, is charged in federal court with kidnapping and unlawful transportation of a minor. If convicted, he could spend the rest of his life in prison.

Mitchell was able to take care of himself and ask for things while in the hospital's forensic unit but refused to participate in any treatments or therapies, Miles said.

"It was the refusal that was a big red flag that he was faking," said Miles, who worked at the hospital for 13 years and was the nursing supervisor of the forensic unit. "He wouldn't engage in any way to move himself along."

SLIDESHOW: The Elizabeth Smart Saga

Mitchell has been diagnosed with a rare delusional disorder.

The hearing in U.S. District Court in Salt Lake City will determine if he is mentally competent to stand trial. A ruling from Judge Dale Kimball was not immediately expected.

On Tuesday. Mitchell's defense attorneys asked Miles, who now teaches nursing at Brigham Young University, whether his mental illness could be "encapsulated," meaning symptoms or delusions could show up in one area of his life while he was high-functioning in other areas.

Miles responded that could be the case.

Defense attorney Robert Steele also asked if the singing that Mitchell did in the commons area of the hospital could be a way of soothing himself.

Miles said it was difficult to make assumptions on that topic because Mitchell would not talk about what was happening or why he did what he did.

Smart was 14 on June 5, 2002, when she was taken from her home at knifepoint. She was found in March 2003 after motorists saw her walking along a suburban street with Mitchell and his now-estranged wife, Wanda Eileen Barzee.

Barzee has pleaded guilty to kidnapping as part of a plea deal that calls for her to cooperate with authorities.

Smart, now 22, gave her testimony in October, saying she was raped after a marriage ceremony staged by Mitchell.

Smart is preparing to serve a mission for The Church of Jesus Christ of Latter-day Saints in Paris. She has not attended the current proceedings.