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 Army veteran suspected of killing four people at a Montana bar last week was still at large Sunday and may still be armed after escaping in a stolen vehicle containing clothes and camping gear, officials said.

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