BERLIN - Hundreds of Germans flocked to the Berlin zoo on Tuesday to mourn the sudden death of the popular zookeeper who raised celebrity polar bear Knut.
"I have been visiting Knut at least once a week since his birth in December 2006," said Berliner Baerbel Roemer, as she laid down flowers in memory of zookeeper Thomas Doerflein at Knut's enclosure.
"Doerflein is one of a kind and I can't describe how sad I am," she said.
Doerflein, who shot to fame as Knut's surrogate father after the tiny cub's mother Tosca rejected him at birth, was found dead in his Berlin apartment near the zoo on Monday.
The 44-year old zookeeper with a thick black beard won the admiration of many in Germany and abroad when he stayed with the polar bear around the clock for 150 straight days, handfeeding the cub milk and porridge through the nights.
A modest man who had worked in the Berlin Zoo for about 28 years, Doerflein said he had received love letters and propositions from female fans after he became Knut's "dad."
"I wrote a letter to express my grief," said crying teenager Jennifer Hennig, standing by a collection of cards and flowers near the enclosure where Knut, now a burly grown bear, paced around.
"I didn't know Thomas personally, but he became somewhat of a friend to me. It hurts when you lose a friend," Hennig said.
Knut was the first polar bear to be born at the zoo in 33 years and some animal rights campaigners had criticized the zoo's decision to hand raise the bear. Supporters pointed out the animal would have died shortly after birth without Doerflein's care.
"We valued him for his selflessness and sensitivity toward all animals," the zoo's director Bernhard Blaszkiewitz said.
"He leaves behind wife, children -- and Knut," best-selling Bild tabloid said in a frontpage headline.
"The bear's dad has died," Berliner Zeitung said, while Berliner Morgenpost daily ran a large picture showing Doerflein and Knut playing.
Knut caused hour-long queues at the Berlin zoo and has become a bona fide celebrity in Germany, with his own brand, CD, book and even a Hollywood offering to film his life story.
"I'm sure (Doerflein) will live on in the hearts of all Berliners who got to know him as part of this touching tale of Knut," Berlin Mayor Klaus Wowereit said.