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.

Four people have been killed during a mass shooting at a Montana bar on Friday, Aug. 1, the Montana Division of Criminal Investigation (DCI) announced in a press release. The shooting took place at 10:30 a.m. local time at The Owl Bar in Anaconda, a city of fewer than 10,000 people.