A manhunt is intensifying for the gunman who allegedly killed a bartender and three patrons at a bar in southwestern Montana, authorities said. Michael Paul Brown allegedly opened fire around 10:30 a.m. local time Friday at The Owl Bar in Anaconda, a city of about 9,000 people in southwestern Montana, according to the Montana Department of Justice.

Those killed on Friday were a bartender and three patrons, ranging in age from 59 to 74, the authorities said. The suspect fled into the nearby foothills.

Law enforcement officers are scouring a mountainous area of western Montana for a military veteran who authorities say opened fire at a bar, killing four people.