Change jurisdiction of juvenile courts and adult criminal courts and change provisions relating to detention and hearings under the Nebraska Juvenile Code

LB 556 would change Nebraska's juvenile justice system by lowering the age threshold for certain serious crimes to be heard in adult court (from 14 to 12 years old for Class I-IIA felonies). It requires courts to hold transfer hearings within 15 days if a minor requests juvenile court jurisdiction, and defines "detention" under juvenile law. The bill also clarifies that mental health statements made for transfer hearings cannot be used against defendants in adult trials, though they may be used in juvenile proceedings or sentencing. These changes aim to standardize jurisdiction procedures between juvenile and adult courts.