the filing of a motion in a district court of the United States with respect to a juvenile nonviolent offense under subparagraph (A) or an arrest for a juvenile nonviolent offense under subparagraph (B), the court shall grant the motion and order that each juvenile record relating to the offense or arrest, as applicable, be expunged. (2) Dismissed cases If a district court of the United States dismisses an information with respect to a juvenile under this chapter or finds a juvenile not to be delinquent in a juvenile delinquency proceeding under this chapter, the court shall concurrently order that each juvenile record relating to the applicable proceeding be expunged. (3) Automatic nature of expungement An order of expungement under paragraph (1)(C) or (2) shall not require any action by the person whose records are to be expunged. (4) Notice of automatic expungement A court that orders the expungement of a juvenile record of a person under paragraph (1)(C) or (2) shall, in writing, inform the person of the expungement and the benefits of expunging the record. (b) Petitioning for expungement of nonviolent offenses (1) In general A person who is adjudicated delinquent under this chapter for a juvenile nonviolent offense committed on or after the date on which the person attained 15 years of age may petition the court in which the proceeding took place to order the expungement of the juvenile record that relates to the offense unless the person— (A) has been convicted of a crime or adjudicated delinquent for an act of juvenile delinquency since the date of the disposition