Detailed Instructions: Write an inquisitive question about a specific text span in a given sentence such that the answer is not in the text.
Q: Sentence: His assertion that the mystery man didn ’ t look anything like modern Native Americans infuriated Northwest Tribes , who consider the remains those of an ancestor and sued for the right to rebury what they call the Ancient One .<sep>Span: infuriated
A:
Why were they infuriated over this claim?