The story of Hope was not meant to end like this. A life lived from the start on the internet has been cut short by a bullet from a Minnesota hunter's gun, robbing researchers of an animal who they have been tracking for years.

The black bear, whose birth last year was streamed on the internet, is believed to have been shot after slipping her tracking collar and being lured by a hunter's bait. Researchers who have been tracking Hope and her family, with the aim of restoring dwindling bear populations, are in the position of trying to protect the identity of the hunter, who came forward to say he had shot the bear.

"We know the hunter and he has been cooperative and helpful in the past," biologists Lynn Rogers and Sue Mansfield wrote in a post on the bear family's Facebook page. "He would never shoot a collared bear – and he would not have deliberately shot Hope."

Hunters prefer younger bears, aged from one to three years, because of the quality of their meat, and more than 9,000 Minnesotans have permits to hunt the animals in what the state calls a "sustainable harvest" from the population of about 19,000 animals.

Hope's young life was followed by wildlife cameraman Gordon Buchanan in the documentary The Bear Family & Me, which aired on BBC Two at the start of this year. Lily, Hope's mother, attracted 130,000 followers on Facebook, even if some of them seemed more inclined to make jokes about eating the family.

Thousands more messages of sadness have been posted since Hope first went missing, and many of them are critical of hunting. The Minnesota Department of Natural Resources fielded scores of angry calls, including some from Britain.

Dr Rogers has been working with bears for four decades, and was able to win the trust of the animals in the Minnesota forest to such an extent that he could place a webcam on Lily's den for her 22-hour labour. He expressed sadness, and cautioned against anger.