Here is the opinion in In re I.W. An excerpt:

As we have mentioned, this case began in 2006 and the section 366 .26 hearing occurred in August 2008. Between those times, mother had provided information about her Indian ancestry to the Department and the Department had sent notices and received negative responses from the Cherokee and Blackfeet tribes. At a hearing about ICWA compliance in December 2008, however, mother revealed for the first time that she had a maternal aunt who was a member of the Choctaw tribe and living in Oklahoma. The Department then sent ICWA-030 notices to the Choctaw tribes in Oklahoma, Louisiana, and Mississippi and resent notices to the Cherokee and Blackfeet tribes. At a hearing in February 2009, the Department reported to the juvenile court as follows: “Attached to an addendum for today’s hearing are letters from the Blackfeet tribe in Browning, Montana, indicating that the Act does not apply to any of the children; a letter from the Jena band of Choctaw Indians in Jena, Louisiana, indicating that the Act does not apply to any of the children; and three letters from the Eastern Band of Cherokee Indians, the Cherokee Boys Club in Cherokee, North Carolina. There is one for each child indicating that the Act does not apply as far as that child is concerned. [¶] Otherwise, attached to the prior addendums and reports are the return receipts for all the tribes that were noticed as well as the letters, tribal responses from other tribes that were previously submitted.”