Authorities say there are signs Michael Paul Brown has been in a mountainous area since he allegedly shot and killed four people in an Anaconda bar on Friday.

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. Investigators say Michael Paul Brown,

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."