(BERLIN) -- Preliminary necropsy results on what caused the death of Germany's polar bear Knut came back Tuesday, revealing that "significant changes" in the bear's brain led to his sudden death.
Berlin Zoo officials said the results showed "no changes" in any other organs, and that further tests were being lined up, including bacteriological examinations. The results from these extra tests won't be known for several days.
The four-year-old polar bear was found dead in his pen Saturday.
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