Whenever a final decree of adoption of an Indian child has been vacated or set aside or the adoptive parent voluntary consents to termination of parental rights to the child, a biological parent or prior Indian custodian may petition for return of custody and the court shall grant that petition unless there is a showing, in a proceeding subject to the provisions of Section 1912 of the Indian Child Welfare Act ( 25 U.S.C. Sec. 1901 et seq.), that the return of custody is not in the best interest of the child.
Ca. Fam. Code § 8619.5