A 24-year-old man was killed by two grizzly bears while he cleaned their enclosure.
Benjamin Cloutier was a trainer at Animals of Montana, a facility that trains captive animals for films, television commercials and public appearances, Reuters reported.
The attack happened on Sunday as Cloutier conducted a routine clean of their enclosure.
A statement from officials at the facility speculated that Cloutier may have fallen or passed out before he was attacked because there were no defensive wounds and he had not used the bear spray he was carrying, AP reported.
"I believe, given all things accounted for, that (Cloutier) was somehow rendered unconscious, whether it be he slipped and hit his head or something else," said Demetri Price, head trainer at Animals of Montana near Bozeman.
"The bears we believed killed him, but we don't believe it was an attack scenario."
But Gallatin County Sheriff Brian Gootkin said there was no way to prove Cloutier was unconscious when the attack began.
“The body had been attacked so fiercely, there were so many injuries that there was no way — that’s why we’re not going to speculate,” Gootkin said.
Cloutier died of bite and claw wounds that hit major arteries and caused massive blood loss.
Price said Cloutier, who had worked as a trainer at the company since 2008, had been in the bear enclosure hundreds of times.
One of the bears, weighing 500 pounds, had to be killed to enable rescuers to get to Cloutier.
Animals of Montana is a wildlife casting agency, which has snow leopards, African lions, and bears.
"What separates Animals of Montana from the competition is the fact that all of their animals are worked with day in and day out from just days old," according to the company's website.
"They develop a special bond with their training, which in turn eliminates misbehaving, unruly, scared animals."