Elizabeth Smart to confront her kidnapper for first time since her rescue

Once he has a floor and a ceiling, the judge can either give Mitchell a sentence that falls within that range, or he can go above or below that range if he determines there is good reason, Cassell said.

A basic conviction of kidnapping in federal court for a person with no prior convictions who did not harm their victim is a 10-year minimum sentence, he said.

Attorneys for both sides of the Mitchell case are expected to argue about a number of possible aggravating factors. Those include whether Smart suffered "extreme" psychological harm, whether Mitchell was the mastermind of the crime or whether he worked hand in hand with Barzee, and whether Mitchell preyed on a vulnerable victim.

Cassell's prediction is that Mitchell "will probably receive a very, very heavy sentence on Wednesday."

Mitchell's attorneys, however, are expected to ask Kimball to send their client to a federal mental health facility.

One question that has been on the minds of many is how Mitchell will react in the courtroom when confronted by Smart. Cassell said traditionally, it is highly unusual for a defendant to act inappropriately during his or her sentencing.

"Usually defendants are on their best behavior during sentencing because they're trying to get the best possible sentence," he said.

But in Mitchell's case, he has sung hymns or disrupted the proceedings for every court appearance — even when jurors delivered their guilty verdict — for the past seven years.

Kimball's office declined to comment about what actions might be taken Wednesday if Mitchell again tries to disrupt Smart when she addresses the court.

E-mail: preavy@desnews.com. Twitter: DNewsCrimeTeam