A. In cases where an adult is charged with violations of the criminal law pursuant to subsection I or J of § 16.1-241, the procedure and disposition applicable in the trial of such cases in general district court shall be applicable to trial in juvenile court. The provisions of this law shall govern in all other cases involving adults.
B. Proceedings in cases of adults may be instituted on petition by any interested party, or on a warrant issued as provided by law, or upon the court’s own motion.
C. Proceedings in cases of adults under the age of 21 who are alleged to have committed, before attaining the age of 18, an offense that would be a crime if committed by an adult shall be commenced by the filing of a petition.
D. Proceedings for violations of probation or parole in cases of adults under the age of 21 where jurisdiction is retained pursuant to § 16.1-242 shall be commenced by the filing of a petition.