Powell County Sheriff Gavin Roselles said the bear had wandered into the campsite a couple of times before the fatal attack.
“A video camera from a local business caught footage of a grizzly bear Monday night, and a bear also got into a chicken coop,” according to the Montana Fish, Wildlife and Parks.
FWP spokesperson Greg Lemon said the attack happened between 4 a.m. and 5 a.m. in the area of Ovando, a town of fewer than 100 people about 60 miles northwest of Helena.
Sheriff Gavin Roselles said a team of law enforcement and wildlife specialists has been assembled in the town to track down the bear.
The identity of the victim has not been released.
FWP said grizzlies, a subspecies of the brown bear, are common in the Blackfoot Valley where Ovando is located. Next to Alaska, Montana has the largest remaining grizzly bear population in the U.S.
Confrontations between bears and people tend to result from the animals’ defense of a food supply or their expansion into private lands and other places inhabited by humans.
The Associated Press contributed to this report.