This was such a sad story to begin with. Knut the sweet Polar bear died at the age of 4. But it was a bit of a mystery. Now the experts have the answers.

The final necropsy results : Knut, who walked in circles before seizing up and falling into the water in his enclosure at the Berlin Zoo, drowned.

Knut The Polar Bear Dead At Age 4

But what caused him to seize up in the first place? The underlying cause was encephalitis, or a swelling of the brain brought on by an infection.

There are three females still in the zoo who could possibly be suffering from the infection as well. The experts also pointed out that even if Knut had fallen in and drowned, he would have died from the disease itself at some point.

Poor thing.