Wanda Barzee, accused of kidnapping and sexually assaulting Elizabeth Smart, is expected to plead guilty in federal court Tuesday.

In a major development in the Smart saga, a court order Monday suggested a guilty plea from Barzee is part of a possible plea bargain in her federal case.

An arraignment/initial appearance was unexpectedly scheduled Monday for Barzee in U.S. District Judge Dale Kimball's courtroom for Tuesday at 10 a.m. It would mark the first federal court appearance for Barzee.

But in a decorum order, Kimball said Barzee "is anticipated to enter into a guilty plea pursuant to an agreement with the United States." There is growing speculation that she will be a "cooperating witness" — referred to in another newly-filed court document — who may testify against her estranged husband, Brian David Mitchell.

Neither the U.S. Attorney's Office nor the Salt Lake County District Attorney's Office would comment Monday on a possible plea deal. When asked about the timing of Barzee's initial federal court appearance, U.S. Attorney for Utah spokeswoman Melodie Rydalch said, "We have always said at the appropriate time we would pull her into federal court."

Ed Smart, Elizabeth Smart's father, said he too was asked by prosecutors not to say anything until after Tuesday's hearing, which he planned to attend. Ed Smart noted, however, "We're aware of what's moving forward, and we're certainly supportive of it."

Barzee and Mitchell were both indicted in federal court on charges of kidnapping and unlawful transportation of a minor across state lines with the intent to engage in sexual activity. That's in addition to their numerous kidnapping and sexual assault charges in state court.

Both are accused of kidnapping Elizabeth Smart from her Federal Heights home in 2002. The couple took her to California before returning to Utah where they were spotted and arrested in Sandy in 2003.

Barzee, after years of being declared incompetent to stand trial in state court, was recently determined to be competent by doctors at the Utah State Hospital. This came after doctors were given permission by the courts to involuntarily give her anti-psychotic medication. An official decision by 3rd District Judge Judith Atherton on Barzee's competency was still pending Monday.

Mitchell was declared incompetent to stand trial and not eligible to be forcibly medicated in 2008. After that decision was made, federal prosecutors opted to go ahead with their case and put the state case on the back burner.