M13 was the 13th male from that group to be born in the wild.

CNN: Switzerland's only wild bear is killed as a danger to humans

The risk remains that other bears might follow in M13's paw prints and stray into Switzerland's Grisons area.

CNN: Switzerland's only wild bear is killed as a danger to humans

Joanna Schoenenberger, an expert on bears at the WWF, said it was far too soon to shoot M13.

CNN: Switzerland's only wild bear is killed as a danger to humans

She uses a well-known and simple virus that usually infects bacteria, called M13, and runs experiments on them, 1 billion at a time.

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M13 "was in no way a problem bear, " she said, adding that wildlife officers should have continued efforts to make him more frightened of humans.

CNN: Switzerland's only wild bear is killed as a danger to humans

When M13 emerged from his winter hibernation recently, that pattern of behavior was repeated, pushing authorities to act, the environment office said in a prepared statement Wednesday.

CNN: Switzerland's only wild bear is killed as a danger to humans

According to the Swiss Federal Environment Office, M13 was one of about 40 individuals originating in the Trentino Alto Adige area of Italy, where a reintroduction program is under way.

CNN: Switzerland's only wild bear is killed as a danger to humans

"The bear M13 had certainly never showed any aggression toward man, but the risk that an accident might happen and that people might be badly injured or killed had become intolerable, " it said.

CNN: Switzerland's only wild bear is killed as a danger to humans