ALFRED – A Biddeford man has been given up to three weeks to make a formal motion to change his guilty plea to the 1998 murder of an elderly woman or face sentencing for the crime.

A judge Thursday refused to allow Christopher Wynne to withdraw his guilty plea in the killing of Claire Emerson, 79, who was bound with duct tape, beaten and left to die.

In a Feb. 17 letter, Wynne asked that the court change his guilty plea, but Justice Roland Cole said that was not a formal request.

Instead, Cole allowed Wynne to change lawyers, from Christopher Northrop to Thomas Connolly, and said any formal motion for a plea change must be made through his attorney.

“I just want to get this matter resolved one way or another,” he said.

Wynne, 21, of Biddeford, faces a minimum of 25 years to life in prison after pleading guilty last August to killing Emerson in December 1998 after he and a friend, Robert Diffin of Biddeford, robbed her house.

The prosecution expressed frustration at Thursday’s court action, which thrust the case against Wynne into uncertainty.

“This case has dragged out far too long,” said Assistant Attorney General Lisa Marchese. “I hope he does go forward with his guilty plea. But if not, we’re ready to go to trial.”

Marchese said she does not think Wynne’s request is a tactic meant to delay his sentencing.

“He’s a young man and he’s looking at a lot of time,” she said.

Northrop would not comment on the case and Connolly was not in court Thursday and could not be reached for comment.