The zoo keeper who raised Germany's famous polar bear cub Knut by bottle was found dead Monday in his Berlin apartment.
A police spokesman Thomas Doerflein, 44, appeared to have died of natural causes. There was no reason to suspect suicide or foul play, he said.
Dorflein raised Knut by bottle after the cub and his twin brother
were rejected by their mother when they were just days old.
Knut weighed a tiny 810 grams at birth, and there were real fears he would die, as his brother did after just four days.
But the bear, who turns two in December, thrived and went on to become the star attraction of the Berlin Zoo, generating millions of euros in income through merchandizing and admission fees.

German exports plunged in November to record the biggest fall in nearly two decades, data released Thursday showed, as the deepening world economic downturn hits Europe's biggest economy.
When the Spirit rover landed on Mars five years ago, no one expected it or its sister rover Opportunity to make it to their first birthdays, let alone their fifth.
The San Antonio Spurs turned up their trademark defense down the stretch to turn back another opponent.
US singer and Academy Award winner Jennifer Hudson, 27, dominated the nominations for the 40th NAACP Image Awards.
After the Taipei Zoo received two giant pandas from China, another Taiwan zoo said Friday it is seeking to receive a pair of pandas from China.