Zookeeper who hand-reared Knut the polar bear found dead

A police spokeswoman said the cause of death of Thomas Doerflein, 44, was not yet known after his body was discovered this afternoon.

Doerflein found fame by association around the globe in 2007 - when he became the personal caretaker for Knut the polar bear at Berlin Zoo.

Zookeeper death: Thomas Doerflein, who hand-reared Knut the polar bear, has been found dead

Knut became a sensation when the zoo decided to hand-raise him after he had been rejected by his mother. But some animal rights groups said it would have been fairer to have the cub put down.

Doerflein was inseparable from the growing polar bear and visitors flocked to the zoo to see the keeper frolick with Knut in his enclosure.

Close bond: Doerflein became a father to Knut after the cute cub was rejected by his mother

World famous: Knut hit the headlines when it was said he should have been put down rather than raised by humans

But in July 2007 the zoo's director banned Doerflein from playing with Knut because the bear had grown too large making him potentially dangerous.

And earlier this year, another keeper at Berlin Zoo, Markus Roebke, said Doerflein's relationship with the bear was not healthy.

Star attraction: People flocked to Berlin Zoo to see Knut frolick in his enclosure with Doerflein

He said: "The trouble is that Knut identifies himself as a human and not as a polar bear.

"And as long as he is with us he will always think of Thomas Doerflein, the keeper who brought him up when he was a baby, as his father."

Growing: Doerflein was banned from playing with Knut after he grew in size

Grown: Knut how he looks today