Stymied by treacherous terrain and untamed wilderness, authorities are struggling to find an Army veteran suspected of killing four people at a Montana bar last week.

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.

Four people were killed in the attack inside the Owl Bar in Anaconda, Mont. The authorities are still searching for the suspect, an Army veteran who lived nearby.