Dear Mr. Weber,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located a series Student Case Files, 1902-1989 in the Records of Bureau of Indian Affairs (Record Group 75) that may include the names of your ancestors who attended the Phoenix Indian School. The records are not yet digitized and available in the Catalog. For access to and/or copies, please contact the National Archives at Riverside (RW-RS) via email at email@example.com. The case files are fully open to the public, since they would have attended prior to 1945. Because earlier school records are not complete, if a case file does not exist, it does not necessarily mean that they did not attend the school.
You may wish to review Phoenix Indian School for background information.
We hope this is helpful. Best of luck with your family research!
[Information provided by Cody White, Subject Matter Expert]