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.

A massive manhunt is underway in western Montana for Michael Paul Brown, 45, who allegedly killed four people at The Owl Bar in Anaconda on Friday morning. Brown, a military veteran, fled the scene in a white pickup truck but later abandoned the vehicle.

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