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.

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.

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."