Washington Revised Code Title 13. Juvenile Courts and Juvenile Offenders § 13.38.060. Jurisdiction

(1) An Indian tribe shall have exclusive jurisdiction over any child custody proceeding involving an Indian child who resides or is domiciled within the reservation of that tribe, unless the tribe has consented to the state's concurrent jurisdiction, the tribe has expressly declined to exercise its exclusive jurisdiction, or the state is exercising emergency jurisdiction in strict compliance with RCW 13.38.140.

(2) If an Indian child is already a ward of a tribal court at the start of the child custody proceeding, the Indian tribe may retain exclusive jurisdiction, notwithstanding the residence or domicile of the child.