Alyssa Bustamante pleaded guilty last month to second-degree murder in the October 2009 stabbing and strangling of 9-year-old Elizabeth Olten in a small town just west of Jefferson City. Bustamante, who was 15 at the time of the crime, now is 18 and faces a term in an adult prison.
The minimum sentence for second-degree murder is 10 years. The maximum is life in prison with the possibility of parole.
The prosecutor and Bustamante's attorneys each will be making arguments during a sentencing hearing that begins Monday in Cole County Circuit Court.