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.

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.

The suspect in the quadruple killings, 45-year-old Michael Brown, remained a fugitive, officials told USA TODAY on Aug. 4.