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.

Four people were killed in the attack inside the Owl Bar in Anaconda, Mont. The authorities are still searching for the suspect, an Army veteran who lived nearby.

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."