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

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.

Police are looking for Michael Paul Brown, 45, after four people were shot and killed in The Owl Bar in the small town of Anaconda, Montana.