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.

Officers are "unrelenting in their pursuit, working around the clock" to find him, Montana Gov. Greg Gianforte stressed at a news conference on Tuesday. "Rest assured, our brave men and women of law enforcement aren’t giving up."

( NewsNation) — Montana officials said the search for the suspect in a deadly bar shooting is expanding as it enters a sixth day. Officials did not give specifics on where the search has expanded but said there are several local, state and federal teams taking part in efforts.