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 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.

Authorities urged residents to stay inside and on high alert because they consider Michael Paul Brown armed and dangerous.