Haw. Rev. Stat. § 571-13: Retention of jurisdiction.

Except as otherwise provided in this chapter, jurisdiction obtained by the court in the case of a minor may be retained by it, for the purposes of this chapter, after the minor becomes eighteen years of age until the full term for which any order entered shall have expired. Further, in the case of any person who is alleged to have committed an offense under section 571-11 prior to reaching eighteen years of age, the court shall have jurisdiction after the person becomes eighteen for the purpose of holding hearings and/or entering orders of disposition concerning the alleged offenses or for the purpose of making and issuing orders for pre-trial detention of persons aged eighteen years or older to an adult correctional facility, when the person is alleged to have committed an act or acts during the person's minority that would constitute a violation of section 571-11(1). This section shall not be construed, however, to confer any jurisdiction upon the family court over a person for any criminal act committed after the person achieves eighteen years of age.