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 shooting happened around 10:30 a.m. local time on Friday at The Owl Bar, according to the Montana Division of Criminal Investigation.

The victims, all local residents of Anaconda, Montana have been identified as 59-year-old Daniel Edwin Baillie, 64-year-old Nancy Lauretta Kelley, 70-year-old David Allen Leach, and 74-year-old Tony Wayne Palm, Knudsen said in a news release.