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

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.

Montana Gov. Greg Gianforte on Tuesday signed an executive order freeing up more resources for local law enforcement as they searched a mountainous area for a former U.S. soldier suspected of killing four people at a bar last week.