Authorities in Montana are searching for a killer who is "capable of truly heinous things" as they investigate the death of a man whose friend told police first he may have been the victim of a bear attack.

Investigators are asking for help solving a "vicious" murder in a remote camping in Montana that was so brutal a 911 caller had reported it as a possible bear attack.

The victim, identified as Dustin Mitchell Kjersem, was found dead in a tent, about 2.5 miles up Moose Creek Road, north of Big Sky.