Police are looking for Michael Paul Brown, 45, after four people were shot and killed in The Owl Bar in the small town of Anaconda, Montana.

The manhunt in Montana is on day 5 for a former U.S. Army soldier on the run days after he allegedly shot and killed four at a local bar in the southwest part of the Treasure State.

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.