The manhunt for the person who opened fire and killed four people at a Montana bar stretched into its fourth day Monday.

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."

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.