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 suspect accused of fatally shooting four people at a Montana bar, who remains at large, struggled with mental health issues but was denied services from agencies that were supposed to help, according to his niece.

A manhunt is intensifying for the gunman who allegedly killed a bartender and three patrons at a bar in southwestern Montana, authorities said.