Stymied by treacherous terrain and untamed wilderness, authorities are struggling to find an Army veteran suspected of killing four people at a Montana bar. But the difficult landscape isn’t the only challenge.

Four people were killed in a shooting at a bar in Anaconda, Montana, on Friday, authorities said. A suspect is at large.

A manhunt is intensifying for the former U.S. Army soldier who's been at large for days after allegedly gunning down four people at a Montana bar.Michael Paul Brown, 45, is suspected of opening fire on Friday morning at The Owl Bar in Anaconda,