§ 32A-28-6 NMSA 1978

When an Indian child is placed in the custody of the department, the department shall work with the parent, the guardian, the Indian custodian or the Indian child's tribe to establish membership, at the direction of the parent or the Indian tribe. The department shall not determine tribal membership. An Indian tribe shall have the sole right to determine membership and membership eligibility, as defined by the Indian tribe's law, custom, tradition and practice. The department shall provide records to assist with determining membership eligibility at the request of the parent or the Indian child's tribe.