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.

Many manhunts end quickly, but the man accused of killing four people in rural Montana appears to have disappeared into the kind of wilderness that helps elude pursuers.

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