The ICWA neither expressly or impliedly restricts the superior courts in its good cause evaluation to the considerations expressed in the federal guidelines. Congress intended to provide the courts with flexibility in determining the placement of an Indian child. A party claiming a good cause exception to the placement preference bears the burden of proof, and a good cause finding is subject to a substantial evidence standard of review. Here, the record disclosed substantial evidence supporting the juvenile court’s good cause finding to overcome the ICWA’s preference for placement of the children with an Indian family. The record showed the two minors (one of whom was of Indian heritage, and the other not) had a substantial bond with each other and it would have been detrimental to separate them. There was testimony that the children had a strong bond with their foster parents, and that moving them would be detrimental. Further, moving one of the children could cause her to develop an attachment disorder. Therefore, the juvenile court acted properly when it denied the tribe’s petition to place the children with an Indian family selected by the tribe in accordance with ICWA’s placement preference, and writ relief was denied.